I have a Hitchhiker II with points of rot. Trim screws on the slides for sure is one of the problems, caulked all of them. Another area on Hitchhikers is the way they wrapped the the bottom of the walls at the point they meet the floors. They used some material that I would compare to roofing felt paper & simply wrapped the wood & stapled it. No caulk. On mine I sealed this point with window sealing tape, (3-M ) & caulked the joint the length of the slide. Road & wheel spray was getting up into this area. Poor construction method. Caught it early enough.