Have a 5er,Want to get a used TC for me.What to watch for?

Sorry I'm only familiar with the older non basement models.

i can tell you an oscillating multi tool is woth its weight in gold when you begin to disassemble the lower interior to get to the rotten floor. These tools excel at making otherwise almost impossible cuts without destroying things. You can even get bi-metal blades that will cut through nails and brads.

i guess the upside is you will have a camper worth keeping once you get it repaired.