I have thought about putting a hole in the top of my F150 but the metal up there is really really easy to press in. I fear it is just too thin to provide adequate strength.
You are right. The f150 is a cracker box.
I have thought about putting a 6 x 6 or 8 x 8 aluminum plate under the hole to give it more support but that would be a job to install.
Put that plate OVER the hole and glue it on over its entire surface. You will get the strength you need and still have good ground connection from inside (just make sure you remove paint there—I also use dielectric grease inside).