I grew up in the era of slide-in campers, and they were very heavy. They also make a 1/2 ton truck top-heavy and hard to handle, especially in a crosswind. The ones with the bunk over the cab must have been designed for midgets- - - - -trying to sleep up there is as close as I ever want to come to being in a casket while I'm still breathing- - - -it's downright claustrophobic up there! If you have small kids they might like sleeping over the cab, at least until they need a potty break in the middle of the night! We've got an 85 Ford F-350 class C motorhome with an over-cab bunk. We only use it for storage, since the youngest "kid" is 48 years old now!
Jerry