Try finding a used aluminum camper cap for your truck. Bel-Air in Cal. makes new ones that start at $549. With a camper shell you still can use your pickup bed during the week and on weekends just throw a Thermarest and sleeping bag in the back.
My 1st truck was a 1974 Toyota HiLux with a camper shell. My MIL sewed curtains for it and my FIL made a bed platform for it, and we stored our Coleman stove, cookset, ice chest, and duffel bags underneath the platform. We camped this way for several years until our first daughter was born and we moved on to a popup. But to this day, our favorite trips to Colorado and Utah were in that Toyota Hilux with a camper shell.