You don't need to drop the rudder to replace the prop shaft. You can simply remove the cutlass bearing and the prop shaft will get by the rudder. The association offers a cutlass bearing puller as part of its tool lending program.

I've had my rudder off twice and I have replaced the strut with a new one and have taken the shaft out twice. I'm thinking that if you pulled the prop off the shaft it will just get by the rudder without taking the cutless bearing.....if replacing the shaft you could always cut the old shaft and remove in pcs. Of course, you still have to get the new one in. As suggested though with a new shaft you should replace the cutless bearing and that would give you extra wiggle room.