Your roof is most likely aluminum, usually uncoated away from vents etc and shiny, proflexrv is very good, I buy 1 quart/litre cans and apply with cheap foam paintbrush. It comes in tubes as well to caulk trim seams on the sides. It comes clear and white. Messy but sticks to anything and everything, hands and clothing as well as where you want it.
I got my 86 a year ago, used a 1/2 inch wood chisel to poke at the sealant on the roof seams and if the sealer moved a bit, soft, carefully removed sealer, followed loose sealer and then applied proflexrv. I kept my trailer roof resealed that way over the years. Roof is the weak point and needs to be checked every couple years.
I had more than 1 layer and water was starting to get under top layer.
With aluminum roof you only need to worry about vent AC openings and where sealed at the sides, front and rear.