I wasn't sure exactly what I was going to do. I let the kids choose a background felt color and at the time, I had some precut felt shapes on the table that I bought at the 100 yen store. Next thing I knew, the two older boys were arranging them as they saw fit on their felt backgrounds. I went with it, and just pinned them and sewed them into place. Then, I sewed a piece of Mario fabric on the bottom edge of the felt, and sewed lines down to provide little spots to slide the dolls into.
All snug in their beds:
I cut out a thin piece of quilt batting and a matching Mario fabric the same size as the felt and sewed them together like the Kittyland. I flipped it around, stitched around the edges, and sewed on a button for easy closing when it's rolled up (of course it HAD to be a star):
These I actually finished before our house hunting trip and let me tell you- WOW! They played with these on the plane, they were perfect sized for the tray. They played with them in the car and at the hotel.
They fly, they flip, they jump, they sing, they get bad guys: