Caulking

ybconway, this year was the first time I ran a line of caulk then sprayed it with spray, an alcohol cleaner . The caulk does not stick to the cleaner when you wipe it off, it only remains in the dry crack.
It made a perfect caulking job and was quick and easy. I'm actually looking forward to caulking something else now.
Sorry, I don't have a passport or an enhanced license. :B

Thanks for the replies. I'll look into the Marine 3m 4200. I have used marine poly sulfide bedding compound for setting glass in a skylight. Strong stuff but is susceptible to UV light.

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.

I imagine "cleanliness" is key for the new Dicor to stick well. If the old is dirty and sun-faded, cut it back to get a clean surface to bond to. So your plan to remove the worst of the original caulk makes sense to me.

By the time Spring comes and you start tackling, the game (and the damage) will be over, final, done, completed, finished etc.

For Dicor lap joint sealant, there's no need to get the old off, or certainly not off completely. If there's a considerable buildup, trim it down (carefully) with a razor blade or similar; then just clean it well and put a small quantity of fresh over, sealing it into the cracks.

Four tubes of Dicor are probably enough to redo an entire roof from scratch. You definitely won't run out.

Incidentally, most of the time the seal between the cabover section and the cab is actually made with a rubber gasket captured between the chassis roof and the bunk board or equivalent and held in with the screws that mount the two together, usually a bunch of fairly small screws driven up from inside the cab. I don't know if your particular model follows that typical scheme or does something unusual, but I would not expect it to rely on exterior caulking for the cab to cabover seal.