Just be sure you are looking for at least a 3/4 ton longbed pickup. A big V-8. gas or diesel, twin gas tanks. Maybe 4x4. A crew cab is nice, but the truck starts to get a bit hard to negotiate in the cities. I'd suggest the models with a jump seat but not four doors as that gets really long even out in the campgrounds!
I had an 8' NCO....not enough room for me and the Mrs. and sleeping two adults in a 48" wide bed was ridiculous. I have an 8' C/O now so the camper isn't any longer, I just take advantage of the area over the truck cab for a second sleeping bunk and a place for more clothes/etc. The tailgate gives us a "back porch" to leave things on and additional seating. The jump seat in the truck cab carries more "stuff" as well.
Note that some Alaskans have their "hookups" through the sidewall and are designed for a Fleetside bed. Others were designed for a Stepside bed so they have no hookups located on the sides.