How would you evaluate a 12-acre mountain cabin property?

[Adam L.]

So an interesting off-market opportunity has surfaced near me. 

12 acres, log cabin, out in the mountains, 30 mins from major airport and metro area. Very 'rural', no cell service, slow internet, etc.

Basically, there's 3 parcels side-by-side, one with a nicely finished 3br log cabin, the 2nd with an unfinished cabin that's been sitting empty for a decade, and the 3rd lot with a horse barn and foundation/framing that could be cleaned/converted into another dwelling. There's a public access boat ramp for a nearby lake/reservoir 10 minutes down the road. The three buildings are all off a shared driveway and all within 500 yards of each other, with the property lines then extending back into the forest for 4 acres each.

Forest, wildlife, hiking, backs up to BLM land. Hell, the owner said he hunts and harvests elk right at the top of the ridge behind the house and shoots a few turkeys each year.

I'm thinking of buying this but the seller is firm on their $700k asking price. I'm thinking I can use this as a family vacation spot as well as AirBnB type property and fix, convert, build out the other two dwellings to use as rentals as well.

Curious if anyone else here has gone through a similar process? Any tips? Any advice for evaluating if it really is a good idea to 'invest' in this rather than stock market or a more conventional duplex type property in town?