I prefer Gorilla tape to generic duck tape; it seems to last better and peel off more easily when no longer needed (and with less residue) than standard duck tape.
Definitely get a #2 square (Robertson) screwdriver. You probably will not be able to remove or replace most anything without one.
A few 12V fuses in various sizes are a good idea.
If you like to burn wood in campfires, a
small Fiskars splitting axe is a mighty nice tool to have. It splits wood far more effectively than a standard hatchet, while not taking up too much space or weighing as much as a full-sized splitting maul.
A level can be handy, too; I think you can find perfectly adequate ones (for RV usage) at dollar stores from time to time.
A few collapsible battery-powered LED lanterns can be handy. I like to set mine out on key spots if I arrive at a camp site after dark so as to give myself some visible references for positioning the RV. I might put one on the corner of the picnic table, or the power post, or that big rock they place so conveniently close to the entrance to the site, or next to the ditch I need to avoid. It saves me a lot of getting in and out and general aggravation.
Despite this arguably lengthy list, I wouldn't go to far overboard with tools to begin with; instead, I'd just buy what I need when I need it while traveling. It's rare to go too far away from civilization (or have something so completely break) that you can't get most basic tools when you find you need them, or at least soon enough afterwards to not be a huge problem.
