Mast wiring is imbedded in cabin ceiling between liner and deck, same as interior lighting. The connections will be found in the base plate when the mast is lifted. If you want to re wire everything I think it would be easier to install a water proof through deck connector, like a junction box,f next to step. A singe multi wire cable would have enough leads for steaming and anchor lights. The cable exits the mast 4-6 inches above with a waterproof plug for deck connection, If you have a wind transducer wire and the vhf antenna to accommodate you can rig something similar. If you can't find the original wiring, it will be PIA to re imbed a new system. I think it makes more sense to install an external conduit to contain all the new wiring. It won't look bad, after a while it will be unnoticed.