To convert my truck into a low cost camper, I purchased a Joy Tutus camper shell tent for my F150. It’s strapped down to the truck and with the tailgate open, there’s enough room for 2.
To make the truck bed comfortable, there are air mattresses that fit the truck and follows the shape of the truck bed. I did not order the mattress yet, but if I do head out to Big Bend national park, I’ll likely order one.
Rolled up it’s a small and light package.