In my experiences I've seen three types of quests. Linear ones that keep you on a specific path and don't detour from it much, roaming quests where the players can go anywhere but there is still a storyline to try and follow along, and a mix of the two.

Which do you prefer, a linear story line or a roaming one, and why?

I would want whatever one makes most sense for the story and the players. Some stories can't be told in a free-roaming world (or are a lot harder to tell) and some players can't handle a roaming one, since it gives them choice-paralysis or choice-fatigue.

In an ideal world, you would be able to shift the position of your game on this spectrum on the fly.

The one I have the most experience with playing in, and certainly is my preference is a free roaming world. We were often given choices on what to do and how to handle things, and a lot of the time was to just walk away and go to a new city or town and ignore certain problems. Out DM always had a great way of working our choices in, and even though we may have tried to avoid a certain quest, it always caught up to us in a big way down the road.

~SE++

This. I prefer a linear adventure, with a freeform choice of which line to start.

As a DM I have always preferred Free Roaming with a story. But I was well aware of the world before they go adventuring and I would hand over an "almanac" of sorts that would explain local customs and legends/stories and politics as well as details on the history of the world and current events. The players are smart, and unless you get a troublemaker, they generally stick to the areas they are meant to for their levels. Otherwise, well, they die. Or meet fates that make it impossible to continue adventuring. Which I take a certain glee in.

As for the story, I would create a number of key encounters and characters that I wouldn't fix to any one particular area, but I would have a sequence they should be encountered in. Then as they roamed, I would occasionally throw one of these story arcs/characters at them. Before long, they would be leading me instead of the other way around.

As a writer, I prefer to give what you call the mix of the two. But really what it is is the illusion of free roaming. And so while this is true for stuff I publish with various companies, it also holds true for GMs. There's a few ways to pull this off.

The most common way is that the GM lays out three (or whatever) plot hooks for the PCs. Maybe they overhear about a lost city that's starting to become uncovered in the nearby desert; a fig merchant has a problem with his shipments being hijacked as they head over the mountains out of the protection area of the city-state; and while all this is going on, the city-state's house guards are waging a battle against drug dealers who are rumored to live in the sewers, but nobody can ever find a sign of them when they go and look.

So now the PCs have three hooks. Each hook has a different locale, and each locale is likely inhabited by different stuff. The lost city is a great place to use undead or evil outsiders, and maybe a few giant scorpions; the fig merchant's problem is going to resolve in the mountains, and that could be anything but lets go with some sort of intelligent, malevolent magical beast. Exactly what depends on your players' level of course. The drug war is going to take place in the sewers, back alleys, and shady locations throughout the city-state, and it's going to involve humanoids (for the most part).

Most GMs look at that and say they need to build three adventures. I don't. I look at that and say I need to have three different maps (maybe), I need to bookmark some interesting undead creatures; I need to figure out what magical beast - I'm likely to advance it with HD, templates, and/or class levels to get the boss, and use the base creature for the rest of the encouners; and I need a pile of NPCs, most of them likely rogues and fighters. that's six different tools I now have at my disposal going forward:

• A map of a lost desert city
• A map of a mountain region
• A map of the city-state's sewer system, and maybe even of a few businesses in the city-state.
• A list of interesting undead creatures
• An advanced magical beast villain
• A pile of NPCs, and bonus points here if some of those NPCs are tied to locations in my city-state, like a bartender or such.

So my players decide they want to help the fig merchant. They like figs, and he's offered them free figs for a year if they can stop his wagons from getting wrecked by the monster. So now I grab my mountain map, I fill in encounter areas with some of the normal magical beasts, I flip through and find one or two other creatures - assasin vines, whatever - to shake up the encounters, and I have my boss beast for them to defeat at the end. Yay, a fun adventure and free figs for a year!

But I still have other tools for when the players come back. I have two more maps I can use either for what they were originally intended as, or I can recycle them later as something else. The sewers just become a ruined keep, for example. My players don't need to know it was drawn as a sewer - they just want to go kill stuff and take their things. The list of undead is something I can always keep tucked away; they make great encounters in lots of things. I can use the scorpion as a set piece encounter the next time they travel through the desert and come across an oasis.

And the NPCs? Wow, that's a gold mine of stuff for me. I can recycle the stat blocks and make them a different villain, or a merchant, or a gang of thugs they encounter after getting free figs. Or I can just level them up later on when the PCs decide, "Hey, we really should do something about the drug cartel under the city. Everybody's getting high and not eating figs. And if the fig merchant goes out of business, we don't get free figs!" It doesn't matter that they're now three levels higher. Advancing those NPCs is a lot faster than building from scratch. I still have my map and city locations to use.

Later on in the campaign, when the PCs go under the sea to take on the sahaugin who have been raiding ships, I can pull out my lost city map and I'm halfway there for having the adventure done.

Finally, as a GM I let other writers do my work for me. Have a few copies of Dungeon magazine? Then you have a big pile of maps and a big pile of NPCs and monsters. You don't have to run those adventures - swipe the map, tab that cool enchanter to be used later on, take the cleric of Vecna and reflavor him (with a slight alignment change and other small tweaks) to instead be a cleric of a neutral god. There's all sorts of little pieces you can suck up from other sources and save yourself some time; the key, of course, is being able to find it when you need it.

So that's how I give my players the illusion of a sandbox world. I keep several plots available to them and keep recycling the content they don't use later in the campaign.

(As a writer, it's a little harder but can be done; it's basically the same thing but on a smaller scale, along with a few ways for the GM to nudge the players back to the plot you buried in the sandbox.)

I give plays several choices and roll with what they do.

When I'm playing "one-off" sessions or a quest over a handful of sessions, I build a small set of linear plots to be pursued.

In campaign mode, which I much prefer, I run literal free roaming worlds. The PC's can do whatever they want, and go in any direction they want.

However, I build worlds. As such, there are actually things going on in the world that are actually going to happen whether the PC's are there or not. The world itself has a set of arching stories that are going to evolve over time, with numerous events that usually lead to some catastrophic upheaval that the players can be a part of if they want to be. Though I've never had a group of players actually choose not to be, even though I would be fine if the players just wanted to stay in the same town using Craft and Profession, living the simple life.

I generally don't run "quests" in Campaign mode. Whatever stories are overarching the greater machinations of the world tend to take precedence and don't leave room for many smaller quests. In that sense, my campaigns typically run a lot more like a 90's Final Fantasy game than a modern MMO. Except unlike a 90's Final Fantasy game, the players usually have freedom of choice (as long as the consequences of a previous choice aren't restricting them) as to where they want to be at any given time, and who they want to support.

I don't make it easy to know which option is "right" — I have had a group of players get to Epic level and destroy the manipulated incarnation of the Sun before, thus casting the planet into complete darkness less than a fortnight before an assault from another world. The players did "win" in the sense that they ultimately survived, but it would be analogous to there being a way to defeat Kefka in FF6 before the World of Ruin...and then not doing that. Things could have gone better.

Good. Choices shouldn't be black and white in campaigns, and there should be consequences for going either way about it. I'm just not a fan of: Kill this guy, he's bad.

~SE++

I find it takes too much time to make a sand box world. If you've been adventuring in the same world for years it's likely that you already have a sandbox world which is easy to just drop characters into our a new plot. If you don't though it's very time consuming which I lost all my world stuff so I don't have a sandbox any more. which means I run a pretty linear campaign. I wish I had a sandbox though they can be fun...

Oh gods, I really want a sandbox world on this forum to get run. I've never run one, and my homebrew world is in its infancy on development... I hope someone runs one sooner or later...

~SE++