If the rocks aren't too large then Cat Tracks would be the way to go. You want the inflated wheels not the Tiger Tracks. They will roll over just about anything. Beyond that a wooden ramp with trailer slides ( for motorboats ) is the only answer. I have the slides on my bass boat trailer and all you have to do is release the winch and she slides right off. In fact, must keep it in gear and running to hook the winch or she slides back into the water.