In general, an Argosy's weak points are the same as a silver trailer's... places where water has leaked over time can weaken or rot the subfloor, the KT latch mechanism in the entry door is delicate, and ham-fisted modifications/"repairs" to the plumbing can be a headache.
The big rear bath is a double-whammy. That's an area prone to leaks from outside (bumper trunk directing water to the seam between the shell and the banana wrap, plumbing vents, big window) and the components of the bath itself can contribute to (plumbing and drains) or hide subfloor damage.
If a deadbolt has been installed, check carefully that it was done right (deadbolt mechanism in the body of the trailer, NOT the door itself, and the bolt shaved down significantly so the hole cut in the edge of the door doesn't have to be too large.
Print the helpful Trailer Inspector's Checklist
and use it. You can skip printing the motorhome pages, of course. If this is your first time using the checklist, I'd suggest reading through it beforehand and thinking about what it's telling you to check, make notes about what's important to you and what's not, etc.
Then come back here and show us pictures if you like it, or if it's a horror show.