To refinish the wood you need to sand all dings, and seal them with epoxy resin. It is ok to fill with the clear epoxy to fill in minor gouges. Bigger gouges can be filled with veneer by scarfing in a new piece. The supplier we had for the mahogay veneer was ML Condon in New York, but I don't even know if they are in business or sell the veneer any more. You should test for leaks at this point, before finishing.
Leaks often develop around the pvc tubes which the forestay and shrouds go through.
A good method for leak testing is to pressurize the tanks and watertight compartment and apply soapy water to any suspicious places. Leaks will cause bubbles to form. Once all the wood is sealed, sand everything to make it smooth. You do not need to sand all the way down to the epoxy. If you are taking the finish off down to bare wood you need to be careful about sanding through the thin layer of veneer on the plywood.