Welcome to iRV2. When looking a used trailer, first thing is the smell when you open the door. If it smells musty or damp, don't bother to look any farther. There is probably a water leak....this leads to rot of the side walls, delamination and floor rot.
Next is a visual look for any signs of leaks. Take a flash light along, look in lockers, cabinets and pull drawers out and look back in the dark area for any sign of water.
Once you have the initial look out of the way, make sure it fits you. Sit in it for a spell and "playhouse". See how you would fix a meal, store dishes, food etc. Try on the shower and sit on the toilet to see if there is room to do the necessary things. Is there a place to store linens and you toiletries? See if you have enough space to store clothes and hang clothes.
If it still fits your needs, you need to hire an independent RV tech to check over the trailer as for all of the systems working properly and check the brakes and bearings. Check the date code on the tires...5 years is the limit on TV tires. You will have to pay him $100 to $200 to get this done. And do not pay the selling dealer for this service as they have a vested interest to sell the trailer at the highest possible price to whoever will buy it.
Have fun shopping.
Amateur Radio Operator (KE5DFR)|Full-Time! - 2012 6.7L Ford Crew Cab Dually -2013 HitchHiker Champagne 38RLRSB - Travel with one Standard Schnauzer and one small Timneh African Gray Parrot