No cap for me
I've had several caps on other trucks, and just can't stand the lack of visibility. The side windows are too small, the back window gets dusty in less than a mile of dirt roads, and most rattle, and create a 'drum' out of the bed and that amplifies the noises.
My preference to keep prying eyes out, and stuff in [and dry] is a good roll up cover. The one I have is called Access, [800-233-4655]. But take a look at the one that Geno's sells, it looks identical.
This cover has a tensioning system, velcro sides, and is a one man operation. It has carried a 16" load of snow, and doesn't turn into a bathtub when it rains heavy.
I will transfer this cover to the next truck if I ever wear this truck out. [not likely]
Unless you need to camp inside the bed, a cover works best for me. Greg L