Re: Would you buy a rental boat?
The average family boat in Ontario logs well under 50 hours a season -- probably more like 30 (I think I did about 60 last season...

) Anyway, don't know where you are located but if you can boat all year round call it a 100hrs average to be generous. So you can see just how much use that thing got in one year -- and probably by people that don't necessarily know how to drive a boat properly.
Now, that's not all bad as others have suggested provided it was maintained properly. All things being equal, though, I bet the lodge owner would rather have his boats on the water making money than in the shop costing money -- especially if he keeps his boats just one season. Can he show you maintenance logs?
I like the fact he's going to fix the upholstry and the promise of a long, pressure-free sea trial is also a bonus. The motor warranty is good news too. Any chance that will cover the outdrive? Shiny new props on high time motors always set off alarm bells for me. Especially with skegs in rough shape. Put the motor in neutrual and give the prop a spin. Watch for out of true rotation. Also, grab the blades and give a good tug side to side and note any play in the shaft. Then, after your ride, haul it again and open up the gearcase drain screw to let some oil run out, and note the presence of water or milky-coloured oil.
Problems with outdrives will get expensive quickly and while not the end of the world it would give you some more leverage in bargaining price. Consider a full survey by an independent professional -- it's rarely money wasted.
Anyway, sounds like you're going in with your eyes open which is good. If you care to post the asking price versus what that boat goes for new it would also help with opinions.