...try skipper bob's guides to anchorages and marinas on the ICW for lots of info and options. Skipper Bob
In general...you will find the southern chesapeake...north carolina...south carolina and georgia the most economical areas to work on a boat. Deltaville VA would be my top recommendation as costs are reasonable and there is a top flight work force inseveral good boatyards and you can anchor out when not having work done. Morehead City NC is another good area for getting work done.