I had a Mazda B2200 a number of years ago. I put a topper on it, laid a piece of plywood in the back, covered the plywood with carpet and underlay. Then I put heavy tinting on the topper windows and away I went. It worked great!!
In some ways better than a truck camper as it was small, light and looked nothing like a camper. When I came back from a trip I just left everything in it and was ready to go when I wanted to. I cooked on a camp stove, carried a cooler and that was it. A lot better than a tent (more secure in bear country) and if it was raining I just climbed out from the back and got in and drove away, no packing or folding.