For that price in a Caravel I would expect a nearly "perfect" trailer. Around $10k is the top end even for the small trailers -- you see them asking more in VAC classifieds and some California dealers, but I think it is rare that such sales occur at full listing price, at least on the east coast.
To me, "perfect" means (at least): no skin damage, all appliances working and in maintained/overhauled condition, excellent/new fabric and curtains, updated running gear (tires, brakes, bearings, hitch components), ABSOLUTELY NO LEAKS, all original glass (not plastic), original furniture in good condition, no soft spots in floor, recently replaced window & door seals, intact/fully repaired belly skin, etc. Some items which typically don't last for more than 30 years, like water pump and A/C should be recently replaced. Usually at that price point a trailer will have been polished as well.
In short, to get that kind of price the Caravel should be in excellent operating and cosmetic condition throughout, with nothing left to be done.
For comparison, I bought a Caravel last year in Maryland which met every criteria on the list above EXCEPT door & window seals, curtains, and polishing. It also had cosmetic skin damage on the curbside and a dent on the roof. I paid about half the price you mentioned, largely because skin damage is expensive to repair.
As far as comfort, that's a personal issue. Personally, I could live in my Caravel (alone) in a warm climate where I could get outside most of each day, but I wouldn't want to try surviving a winter in there!