I used the 3m 4000 for every side seam, marker light, trim and door on the outside of my MH. I like the fact its a caulk and an adhesive all in one. Most import is its UV protection. Been 4+ years and still holding up great. Its was designed for marine use bedding cleats and such.
I used eternabond on my roof seems. No brainer do it once and be done with it. I also used eternabond double sided for my windows. Removed each window cleaned and applied eternabond double sided. Same 4+ years and no leaks.
I only wanted to do these fixes once. Couldn't understand using something that has to be redone or touched up every few years.
Good luck with tour project.