An expansible body structure for recreation vehicles, the expansible body structure comprising:
- a carriage assembly having a plurality of wheels, a rigid body shell enclosure having a means for mounting onto the carriage assembly, the rigid body shell enclosure comprising a roof section, a plurality of sidewall sections defining a main living space, the plurality of sidewall sections including a front sidewall section facing a direction of travel, a rear sidewall section facing an opposite direction to the front sidewall section, and a plurality of side-body sidewall sections, and a floor section having a plurality of cut out areas where the floor section overlaps with the wheels of the carriage assembly allowing the floor section of the rigid body shell enclosure to have a placement on the carriage assembly at a height substantially lower than a diameter of the wheels, the side-body sidewall sections of the rigid body shell enclosure each having at least one substantially large opening, an extendable slide-out assembly mounted inside the rigid body shell enclosure at one of the large openings, the slide-out assembly comprising a floor section having multiple levels, a plurality of sidewalk, and a roof forming a room extension with one side opening toward the main living space of the rigid body shell enclosure, another side of the slide-out assembly facing an outside of the vehicle having an opening for egress, the slide-out assembly having a means to extend through the respective large opening of the rigid body shell enclosure from a retracted position to an extended position to provide a larger living area in the main living space, the slide-out assembly having a means to retract the slide-out assembly from the extended position to the retracted position having the another side of the slide-out assembly flush with the respective side-body sidewall section of the rigid body shell enclosure, the multiple levels of the floor section of the slide-out assembly comprising a main floor level connecting to a substantial portion of the floor section of the rigid body shell, an elevated floor level above the wheels of the carriage assembly, and a sunken floor level at the opening for egress, the elevated floor level having a plurality of sidewall sections forming a wheel well box having an opening facing the wheels of the carriage assembly, the volume of the wheel well box is substantially large and the elevated floor level of the wheel well box having a height substantially above a top of the wheels for the wheel well box to clear the wheels of the vehicle during the extended and retracted positions of the slide-out assembly, the sunken floor level at the opening for egress comprising a sunken floor area and a plurality of sidewalls forming a step-down entrance door well having an opening facing the outside of the rigid body shell enclosure, a width of the entrance door well opening facing the outside of the rigid body shell enclosure having substantially a same width as the opening for egress forming an egress opening extension for a taller egress opening, the slide-out assembly having stop walls along edges of the plurality of sidewalls and the roof to form a weather tight seal between the slide-out assembly and the rigid enclosure body shell enclosure, at a location of the respective large opening of the sidewall section for the slide-out assembly to extend and retract through, the floor section of the rigid body shell enclosure having a substantially large cut out area to allow the main floor level of the slide-out assembly to be installed directly below the floor section of the rigid body shell enclosure, with the sidewalls, roof, and the wheel well box of the slide-out assembly protrude above the floor section of the rigid body shell enclosure, the main floor level of the slide-out assembly having substantial size to provide floor coverage for the large cut out area of the floor section of the rigid body shell enclosure when the slide-out assembly is in the extended position, the floor section of the rigid body shell enclosure remaining above the main floor level of the slide-out assembly when the slide-out assembly is fully extended in the extended position, the expansible body structure for recreational vehicle configured to be in the form of a towable trailer, or part of a motorized recreational vehicle having a driving cab area abutting to the front sidewall section of the rigid body shell enclosure, for a vehicle operator to operate the vehicle.