Don't use anything from the hardware store. Go to Camping World, and get caulking made specifically for RV's. You will need 2 different kinds. They sell a self-leveling style for use up on the rubber roof, around the vents and anything else up there. Cover screw heads with it too. If it were me, I would get new vent covers and install them. Just the part that rolls up and down. They get baked by the sun, and will crack and start leaking right when you don't need for them to! There is a different type caulk for the corner seams. Caulk around all of the lights and windows. Look in the section at Camping World where the caulk is, and there should be some cleaner to use that won't harm the EPDM rubber roof. Our camper is set up permanently in a campground in Myrtle Beach, and I clean the rubber roof 3 or 4 times a year. I use Blue Coral car wash soap to clean it with instead of bleach, as it's not as harsh. Good luck to you, and enjoy it.