We had a '97 Adventurer that had some delamination but most of it seemed to be related to leaks around a window, the exterior access door to the fridge, and another exterior door (previous owner had not attended to some leaks). In my opinion, you should not have a lot of water into your sidewall due to the caulking issue you describe unless it has been that way for some time. The edge of the roof material overlaps the side wall (not much but some). Seal it up and check the entire seam. If you plan to keep your Winne, might want to consider using Eternabond tape on that seam and you will never have to caulk it again.
'07 Country Coach Allure 470 Siskiyou Summit #31578, Cummins ISL 425; 2014 Ford F150 toad; Air Force One Toad Brake.
Glen Allen, VA; Smith Mountain Lake, VA.