One thing I think is being overlooked is the landing. Somewhere above sushi states that he is going to be landing in 18" deep grass. In my short experience I have winessed several planes perform emergency landings in approximately 18" tall grass in the hay fields around the club, and I do not recall any of them coming out unscathed. John your dolly seems to be a fantastic system, but would it not make since for him to shoten the wheel base a bit to aid in rotation on takeoff and temporarily attach the dolly to the plane simply by wrapping rubber bands up and over the wing so it stays attached with out any permanent mounts. You could add a servo for the steering, and use a Y harness to control it. I Dont know how heavy your setup is, but it does not appear that it would be too heavy to really affect the flying charecteristics too badly. You would need to check the balance of this prior to flight, but it could be built. Also make sure that the width of the rig would remains tight to the sides of the fuse to keep the rubber bands from interfering with the ailerons. It's not very pretty, but it could work.