I have been continuing on the camper and have finished the left and right side frames.
I decided to go with a one foot square window based on the available space in the panel. Here the camper is folded out with both sides now.
The small lawn mower wheels I was using have now been replaced with larger 10" Harbor Freight Worry Free Tires. They feel like pneumatic tires but use foam that makes them perform similar to a pneumatic wheels. The larger size helps since the folded camper is getting close to 200 pounds (estimate -I will weight it at some point).
Next will be building the doors, window and skylight.