I would reconsider
Right not the boat market is certainly a buyers market. You have a 42, that apparently was a bargain. Hopefully you know the condition, and you said nothing about it being in bad shape. Sounds to me like you have a fantasy of moving down a few feet, still having plenty of room, and making a pocket full of money in the deal. More than likely it won't work like that. Boats are not selling very well right now. I just sold a 28, and at least in my mind had to practically give it away. I would recommend you keep what you have, and sail it. Unless of course, you just don't like the boat.