Just a note on the use of Silaprene (you can buy ProFlex at most RV dealerships, it is the equal of Silaprene):
Be prepared to work quick and use a rag and mineral spirits to clean the area and smooth out the caulking. This stuff get's sticky quick and can goop up if you apply it thick. I cut the nozzle tip very small, just large enough to insert the metal rod to break the inner seal. Use some painter's tape and mask the lines where you want to apply the sealant. Apply the sealant, with a rag and some mineral spirits wipe the caulking line and remove the tape.
You now a factory looking job on your camper!
2013 Jayco Eagle 334RBTS
Crossroads Forum Lurker