Be warned about mounting the antenna on the laminated body widewall materials. Hit a branch with the antenna and the base mounting holes can loosen or enlarge the bolt holes in the sidewall. Then it's a leak. We had such a mount, such a leak, and an expensive body repair. This time I plan to use a mirror bracket mount. We have the tripod "box truck" mirrors, not the single arm Velvac's. On our Ford Class C, the doors are NOT grounded. I grounded them with wire for another project, so that's behind me. The braid from antenna cable is probably better as an "RF ground" so I may do an upgrade.
Oh, with Fords, can't take a magnetic mount and go "unicorn" like ^^^ pic. The hood is plastic.