How long can moisture stay in walls?

I am wondering how many others have had this problem with the drip rails and have not found the source of the leak yet. I spent a summer trying to find a leak in the fwd section of the MH. I sealed all the openings on top, clearance lights, tighten AC screws to compress gaskets, sealed front and rear caps multiple times and it still leaked. Finally took my wife's vacuum cleaner and blew air where I saw the leak and saw water coming out of the drip rail 30 ft away in the rear. I have resealed this multiple times and in several locations over the years. Based on my experience I think sealing with tape would be a good idea. To remove moisture before repairing the side walls I parked the MH in the sun for a week and it was still wet. Took a heat gun on low to remove more moisture. Finally sprayed acetone on wet luan. The solvent will flash of quickly and remove the moisture when it does. I think water will enter the rail sit in there and eventually rust out the screws then enter the inside wall. These leaks are hard to find. I think as others have said creating several openings and parking in the SW sun for several weeks would help remove any remaining moisture. I would also compare your good wall with your repaired wall readings before you do anything drastic.