I came across this article, for persons interested in buying and restoring an old boat. I think it has some very good advice. I agree, it is a costly endeavor but to some people it is the only way to go. We bought our "old boat" not because it was a financially sound decision, but because we couldn't find a boat with a better layout and living space.
This is a great website for those who are looking for ideas and tutorials on boat building and restoration: https://www.boat-renovation.com/boat-building/