Consider making your own GMC Sierra into a simple camper with a HEST Dually Long camping mattress. Here is how our HEST Dually Long camping mattress fits inside the bed of a first generation GMC Sierra truck bed.
First generation GMC Sierra truck beds (1999 to 2006) are 79.2" in. long by 71.4" in. wide. With a GMC Sierra 1st Generation our Dually Long mattress will fit between the wheel wells with the tailgate closed.
GMC Sierra Pickup Truck Bed Dimensions First Generation (1999-2006):
