I used to get up on top of my coach at least once a year and I used to caulk with Dicor. As I have gotten older it has become dangerous for me to be doing this. One slip and if you fall from the top from almost thirteen feet, you are dead. So about three years ago I decided to Eternabond every seam on the roof because I did not want to be caulking every year. I bought the four inch rolls of Eternabond through Amazon and done the whole roof. Best investment I have made on my coach since I bought it new.
Sometimes a water leak on the roof can be hard to track down because the water leak might be in the front, but will travel between the roof and come out somewhere else. Kind of like electricity will come out where there is less resistance.
It took me a few years to believe people that were already using this stuff and as to how good it really was. Believe me they were right.