I think you can do it for
Less than $20k. Just depends on what all you are doing and what materials you choose. I think it would be foolish not to replace the fuel tank, foam, and transom while she is opened up. Tanks run $250 - 1200, depending on size and material. New deck and transom could probably be done for $1500 using the very cheapest materials, $12 - 15k using the very best. The elephant is the labor. Do it yourself for a case of beer a week. A top line pro will cost at least $10k, probably more. Do some of each for something in between.
I'm doing mine sort of middle of the road. I demolished it myself, but I have hired some help to rebuild the deck and transom. Putting a big nice new aluminum tank in and using Coosa board on the transom and anything structural. Good marine plywood for the deck. I'm budgeting about $5k for tank and materials , and about $3 for labor. Then I'm adding a Porta bracket and new motor for$16k. So, $24k total? I've got my fingers crossed :)