The things I would be intrested in making sure was in good condition would be:
Springs, Axles - These seem to be a problem and need to be in good condition to safely pull
Jacks - Especially if the electric ones are on your unit.These seem to have had a lot of problems.
Slides - Make sure they do not leak and all the seals are in good shape.
Most of the other items have a mfgr warranty and are not critical to move or live in the trailer. Sure it is important for the Reefer and such to work but if you can't move it or live in it the rest is easier to replace.
Just my thoughts.
BC