A full-size pickup truck can fit up to six people comfortably if it has a front bench seat. Without the front bench, a truck accommodates five people. The beauty of a truck's rear seat in a crew cab is that three child-safety seats often will easily fit across the rear bench. full-size pickup truck can fit up to six people comfortably if it has a front bench seat. Without the front bench, a truck accommodates five people. The beauty of a truck's rear seat in a crew cab is that three child-safety seats often will easily fit across the rear bench.