Mark,
Do you have a 2" receiver hitch? If so, long drawbars are available. One good source is the Hitchhaul Company. They make those "back porches" that fit into trailer hitches. I have seen them in the J.C.Whitney catalog.
If you need to move a boat back on a trailer, you can restore balance by moving the axle back. Many cat sailors have overloaded the front of their trailer with boxes and containers and should adjust the axle location if possible.