One area to also check would be all the areas where there are screws going through the side wall of your trailer,especially along the top.
We had a leak along one side of our rockwood 8315SS. 2 years ago,upon opening the trailer for the season,i noticed water stains at several points inside the trailer. at the kitchen window,at the top of the entry door and inside the rear storage area plus what looked like the start of some delamination on the outside wall of the trailer. i assumed that since we had a heavy snow that winter,that may have accounted for the leaks. but,just to be on the safe side i decided to "eternabond ALL the seams on the roof.got the tape,applied it and thought all my leaks were stopped. several weeks later,opening the trailer we discovered a wet spot on the bed and discovered that water had leaked from the a/c vent above the bed.we still had the leak. next,check all the possible water entry points.i checked where any screws were going through the side wall. after removing the rubber strip on the top rail,(the rail that holds the roof fabric where it overlaps the side)i saw that most of the screws were rusty(on a 2008 trailer).Hopefully,i had discovered the water point of entry. I decided to replace all the screws in this strip with SS screws,(about 70 on each side) about 1/3 of the screws were totally rusty and some were even wet !i replaced all the screws,made sure they were snugged up tight,and even dipped the threads in dicor caulk before i screwed them in. Now after 2 years,absolutely no leaks at all. one thing i will do is to recheck every year the roof tape and retighten all the screws that i replaced. this picture is from my neighbors trailer who had the same problem that i had.not only are the screws rusty,but were also loose,allowing water to seep into the side.
2008 rockwood signature ultra lite 8315SS[SIGPIC]