50 feet per round, a round is 6 seconds, so.... 500 feet per minute.
5280 feet in a mile, so.... you move at about 10.5 miles per hour.
The destination is approximately 10 miles as far as you know, so assuming you get lucky, and it's around 2 pm right now, you could make it out there and back in just over 2 hours assuming you go the exact right way. Now, all of that is simply going off the information given to you by an NPC.
There's also the thing about moving at top speed constantly. According to Google, the average human walk speed is 3.1 miles per hour, and you're attempting to do more than three times that for two hours straight. Personally, I'd feel like you'd be going slower than the max 50 feet per round since you're aiming for sustained travel, so perhaps three to four hours.
Then you're going to have to search for the area, which, depending on information given could account for several more hours, especially since you have no details of what this rock formation looks like, and even with a verbal description, things will look drastically different from an aerial view than the descriptions given from a ground view.
So, if you'd like to go for it and search, I'll give you two options:
(1) Stay in Red Larch.
(2) Roll a percentile (all assuming you leave now, approximately 2 pm).
- 81 - 100: You find what you're looking for quickly and return by 5:30 pm (dusk just setting in)
- 61 - 80: You find what you're looking for and return by 7:00 pm (twilight has fallen)
- 41 - 60: You find what you're looking for and return by 12:00 am due to difficulty in low light (midnight)
- 21 - 40: You do not find what you're looking for and return by 2:00 am due to exhaustion and difficulty in low light (pitch black)
- 01 - 20: You do not find what you're looking for and are stuck in the woods until dawn breaks
Now, things would go differently with more eyes, and those percentiles aren't accounting for potential attacks that you may encounter on your own. But, with sketchy directions and only a loose idea of what you're looking for, that's what I can offer you, and that's a whole hell of a lot more info on choice than I'd usually give a player. But, I've been told I can be hard on players, so this is the most fair chance I'll give you.
~SE++