Sailboats are designed to lay on the ground when the tide goes out (or at least should be). Lift the front of the trailer up about 6 inches then put a pad just in front of the trailer pads supported from the ground. Then you can drop the tongue of the trailer out from under the boat near the front pads so you can paint the boat above them. Same for the stern after paint is dried and the bow is dropped to the trailer.
fwiw Story passed on to me after the daughter of the PO sold me his boat. Unimaginable to me by the way, at the time but believed when it was explained. He had been informed of unexpected loss of access to his sailboat and decided to get everything shipshape including the pieces and parts necessary for a properly equipped sailboat before it was too late. Having been a painting contractor in Idanha Oregon he had made it clear to his family that the boat would have a proper bottom job before he was done with it. As it turned out he had a good size second growth mature fir tree in his front yard and apparently had decided laying under the boat and sanding and painting the bottom wouldn't be an option for him later in the progress of his endeavor. As it turns out the technique he chose to use and one that made absolute sense to him was back the boat up to the tree. Did I mention this is in Oregon where most everybody is expecting to be a logger because that's where the money is and then we find out those logs are worth even more when well painted, while not nearly as deadly. Anyway he had rigged the tree so that he could lift the bow of the boat about 35 feet towards the top when he was ready to hoist it up there standing on its stern. She told me he did get it painted and it stood there for quite a while with its bow towards the sky waiting to be finished after he was gone.
