xxjanaleexx - You may wish to read this posting -
http://www.rv.net/forum/index.cfm/fuseaction/thread/tid/15194642.cfm Do take the RV for a drive over a variety of road conditions. See if passing semi trucks cause the RV to want to switch lanes. Drive over some rougher roads to see how many annoying rattles you hear. Get up to speed to see if the RV stays in the driving lane or wanders left and right.
To answer your question about where there might be wood rot, it would be the ceiling above the cab-over bed. The leak would usually entrap water between the outer and inner wall of the RV. Many RV's have wood framing.
Later years like my 2002 has steel framing sandwiched between fiberglass exterior and interior walls.