The folding ping-pong table would allow an interesting track plan. (5' x 9') You can find those on craig's list at varying prices. You could make scenic items and such removable and store those elsewhere in containers. I would suggest Atlas sectional track for this.
Another thought is to build a modular layout. Assemble it in the family room for a run day and store it when not in use. A 5' x 9'(105") in the LCCA/Lionel modules would be 4 small corner and 2 straight modules. Each is 3.5" thick and very lightweight. FasTrack would survive outdoor protected storage, like a shed, but not open air in the carport. Scenic items would still be detachable and stored in containers. I have attached the specifications for you.
Some have built fold-downs into the walls. Pull an outlet cover and check the exterior walls for use of 6" wall studs. This option is a lot work.