I'll respond to noisy in a pm also. If you want to buy, do these, not this in order.
1- get an attorney to set up an s corp - it is the operating entity
2- Also an LLC, it is the owning entity to which the s corp pays rent, thus you.
3- new appraisal by a disinterested party.
4- research inspections and licensing by the various county, state & fed. ( EPA is notorious for jumping in with upgrade rules!)
5- Get a commercial real estate broker to advise on 'opinion of value' .
Camp sale values vary by region, length of season, condition of infrastructure.
3 rules of thumb in our 5 month season area are that a property in good order will value at about 4-5 times annual gross, or another is 12-16% capitalization rate, last is county assessment at about 80% of real value. How to apply these figures to your region I could not guess. That is why you need professional advice. A brokers opinion of value,
Approach this at 'Arms Length'. The sellers sound like honest hard working folk, but there are possibly regulatory issues that may arise they and you are not aware of.
Our camp had undeveloped potential, which made some blue sky reasonable. What do you see there? Can you, are you willing to do most of that development yourselves?
see you in pm's ( edit) to discuss your personal life impact.
Max