I still haven't completely emptied the boat, but I have already done several jobs. All "water tight" hatches removed. They all leaked, and it turns out none had been bedded on sealant fully. I bailed five bucket loads of rain water out of the stern cockpit lockers. It must have all got in through poor seals.
I have also rerouted the cable from the solar panel into the cabin in a route that keeps it away from various ropes. This require the companionway hatch being removed, but that needed some repairs anyway, so it needed to come off.
I have also been planing down the timber trim around the cabin roof. It has always stood slightly proud of the roof, making a potential water trap. A sharp block plane reduced it to flush all round and my wonderful new multi-tool has sanded it all smooth in no time. I love it.