I've been down this road twice now; it's more complicated than it seems. What camper are you talking about? An 8' pop-up, a 12' triple slide, or something in between.
A flatbed with bolt on tool boxes is far easier to configure for the camper you choose and then reconfigure if you ever change campers.
If you get a fairly "standard" utility body with doors and compartments know that NO CAMPER with a bathroom will fit without modifying the bed.
Until I sold it, I had an 11' camper with no basement and no slides on an aluminum flatbed on a Chevy 3500 dually. It weighed about 13,000 pounds. Unless you want a very basic camper and truck with no options and pack very light I would be looking at a dually truck.
Pop-up campers aren't necessarily lighter than hardside units of the same size. The extra reinforcement and the lift mechanism counteract a lot of the supposed weight savings. Also, pop-ups have no upper cabinets inside so much less storage.