RE: Any Interest?
I think you would be better off just coming up with a price for the week for the cabin. For example, $1000-1200/wk and you set the limit of people using it. That way, if 4 guys want to split it or 10 guys, you still get the same.
In the first scenerio, I would say that the $500 covers the first 2 people (not many people are going to rent a cabin just for just themselves), then $100 per person thereafter. However, if it is really in a good area, I don't think you would have trouble renting it at the above set price, and you might make more money that way.