Try one of those pull bars on the front wheel. Not only allows it to maneuver the trolley around the dinghy park with ease, but it can also be used as a lever to pull the boat back on to the trolley.
By connecting the painter half way up the bar you create a 2:1 purchase and more of you knot it lower. Even without a purchase, with the painter wound around the handle bar I can single handed get my boat back on the trolley simply by pushing the bar down with my own weight. This only works when the bar is at a 45 degree angle. And obviously I have to repeat it a few times, taking in some of the painter each time.
You could also mount a winch on the trolley like people have on trailers (non combi trailers obviously). I have seen it done by an elderly couple, who used a winch to haul out their boat effortlessly.
Last one: Tie the trolley with its axle to a tree behind the trolley. Then tie your boat to the towing hook of a car positioned in front of the trolley. Jam it in in first gear, throttle up and let the clutch come up slowly. I have seen pictures of this process somewhere on the Canadian web site.
BTW, have someone film the event to share it with us on you-tube. If you do, by all means, let the clutch come up quickly 😈