Where I sail (a lake) we have a couple of people who use a small bouy with about 20kg of weights on a rope; before they launch they take this buoy out 20 feet or so and drop it. When they come in they tie the boat to this while they get their trolley. Job done.
I have been using a simular method. I pound 2 stakes into the beach in a crossing fashion. I tie a 100 foot (33 meter) line to them, i tie the other end to the wheels. I role the boat into the lake to rig the main and then sail away leaving the wheels floting around. When i come back i'm able to retrieve the wheels and get the boat attached before i drop the main.
