An accessory support platform is provided for supporting a removable accessory, e.g. a stair system or cabinet, adjacent to a vehicle or portable living quarter, such as a truck-bed mounted camper. The accessory platform includes a support frame for coupling the platform to the truck camper. The support frame supports or suspends a support rail system from the rear portion of the truck camper. The rail system includes an upper support rail and a lower support rail that is suspended below and apart from the upper rail. The removable accessory may be coupled at one of or between both of the upper and lower support rails. The removable accessory is preferably readily repositionable relative to the upper and lower support rails. A coupling bracket and/or hanger secures the removable accessory to the rail system.