There are some really good bargains out there right now in the yacht market. With some careful shopping and working with a Marine Surveyor, I think that this can be a very good option. If the structure, mechanicals and electrical system are overall in good shape and the price is reasonable you probably have a good candidate for a refit.This site has some very good articles on refitting older boats. If you are considering working with an older boat, it would be worth your time to look at what he has written.
For an extensive refit it is often less expensive to use independent contractors rather than a repair yard crew, especially for woodwork. The experienced independent marine carpenter is commonly very skilled and usually has lower overhead than a repair yard, so commonly they charge $10 to $20 per hour less. Over the course of a large job this can make a big difference in the final cost.
For the interior that could range from some new fabric and hardware, more of a re-fresh, to redoing the master, galley, salon and pilothouse. How about turning that rarely used extra stateroom into an office? Is the entrainment center designed for a 1990’s TV and audio gear?