My rig is a 2018 Forest River ex rental, 40,000 miles. There is a crack in the sealant between the cab and the house above the windshield. I ordered 4 tubes of Dicor Lap Sealant and because I'm lazy...
I use Dicor lap sealant on my rv roof and marine 3m 4200 on rv vertical seams which is much easier to work with than proflex rv on the vertical seams. It also lasts for years. Ive been using it on my boats for years.