Welcome to the forum.
First, make sure the wheels turn and the hitch hitches. Then check for leaks
. If it's been parked unused for a while, put some damp rid, or similar in there, otherwise everything is likely to mildew again.
Seriously, don't go by anything the PO told you, check and double check it all. Pull the wheels and repack the bearings and put in new seals. If it has brakes
, check them. Check continuity on the brake wiring and ohm out the magnets. If everything in there is rusted, replace it. You may be able to have the drums turned if they aren't too bad. On all of this, if you are not sure what to do, go to e-trailer.com. They have some great information and videos that can save you a ton of time searching.
If you have a propane
stove and refrigerator
, check for leaks
with soapy water in a spray bottle. On the refrigerator
, check it on AC to see if it works. If it does, before trying it on propane
, save yourself some grief and clean the burner. There have been some excellent discussions of this recently.
Do check the hitch and safety chains. Make sure the stinger is the right height for the trailer to ride level.
Make sure the lights
work. If they don't, check the ground before you do any further diagnosis.
Drain and clean the fresh water tank. Make sure the grey water and black water tanks are empty. It wouldn't hurt to flush them.
This was all real quick off the top of my head, but it should keep you busy for a couple of days.
Also, go to the top of the page and click on MORE and then on DOCUMENT CENTER. There is a bunch of good info there.