I would suggest planning on spending at least 2-3 hours with the trailer BEFORE you finalize any documents.
Be prepared to get on the roof, crawl underneath, walk all around the exterior, try every latch, every door, check every light, make sure that every appliance works, the water works, the drains work, the interior lights, cabinet doors fit and finish, etc. In short, don't be rushed, but take as much time as you need. Identify every issue, document in writing and in photos, then agree to a plan to address them. Don't be afraid to say "I'll come back next week after you have had a chance to take care of these things". Once you drive off the lot, getting it back for a timely repair is next to impossible, and it will be you bending over backwards to try to get them to fix something rather than them getting things done so they can complete the sale.
When we picked up our Cougar a year ago, we spent a good 3 hours there. I had given the dealer a heads-up ahead of time and they had the camper in the shop, hooked up to power and water and a drain line. They had a mechanic's creeper for me to roll around underneath, and a scissor lift to get me on the roof without having to climb a ladder. I checked everything and I mean EVERTHING. What few things I found, they had a tech following behind taking care of them right then and there. Only once we were done and I was either satisfied with the repairs or we had a plan established to address anything remaining, I had them write up a "We Owe" so that it was in writing. Then and only then did I give them the check.