Teardrops n Tiny Travel Trailers

I have mostly finished my first pop up square drop, I'm adding an emergency window to the front. My kids are growing and while we fit in the current 5 x 8 with 6' of headroom, I want to be prepared. My current design is on a 5 X10 trailer that will be custom made. The front and back will be extended upwards about a foot off the frame, making it 12' long. There will be a folding full size bed in front and bunk beds against the back wall, I'd love to sneak in at least a toilet. I like the rockhopper design but would like to start the lift after the front slope. The top lifting portion of my last build was a 1 X 3 skeleton with 1/4" exterior and 1/8" interior plywood. I believe it's definitely strong enough. Could the floor be 1 X 3's and 1/4" plywood on both sides and still be strong enough? I'm hoping for 1,500 pounds.