I'm going up on the roof to do some projects. While I'm up there I would like to re-caulk the end caps and several fixtures.
Whats the current suggested caulking type/brand?
Dicor Self-Leveling Lap Sealant, IMO.
Not cheap but by far the best product for the application It stays pliable, sags slightly to fill seams, and sticks to what it is supposed to. Easy to remove a decade later.
I spent a lot of time earlier this year removing silicone caulk from my RV roof, and reapplying the correct product.
For 20 years we use GE Silicone, usually clear. Understand some use other products. Silicone is not paintable. Prepare surface with denatured alcohol.
Don't use silicone. I like 3M Marine Adhesive Sealant 4000 UV for roof top stuff. Strong bond, removable if needed. Dries quick enough to not attract dirt.
The 3M 4200 Marine Adhesive Sealant Fast Cure is a different formulation, cures slightly faster especially at the surface and is a bit stronger bond and harder to get apart but possible.
I did my rear seam, remove all of the trim, clean it and the roof joint as best you can. I put down painters tape close to where the trim was fitting when reattached, gooed it up, put 4000 on every screw and screwed it back down. Cleaned up the excess, smoothed out the roof to trim joint and pulled the tape. Looks good. Wear latex gloves. WD40 works pretty well for cleanup.
And then I painted the roof with anti skid, insulating polyurethane paint right over the cap trim strips.
This is what I used as well, per Keith Risch's recommendation.
Over the years I have found that 3M products are hard to find fault with.
Ohh gosh for the love of all things please don't ever use silicone to as a flashing caulk on an RV. That is all that the caulk is, a flashing. The seal that really keeps the water out of anything is where the two surfaces come together with a mechanical force (screw, or rivet etc) and a sealant between the two surfaces. The main reason to use things like Dicor is that it is REMOVABLE. Ever tried cleaning old silicone off a surface, nightmare. Ever cleaned off old lap sealant, easy!
One other note is to always try to use the same material on top of existing. If you are unsure of what is on the joint currently the best thing to do is remove the old flashing sealant and clean thoroughly then apply new sealant.
This advice comes from years of experience repairing and rebuilding water damaged RV's. I have seen all kinds of gunk on a seam. Also check out James the AZ Expert and he has a ton of great videos showing how to do things. AZ Expert on Youtube (https://www.youtube.com/c/AZExpert/search?query=sealant)