Totally agree with Theo and Sunil.
Did you take any of your expenses on the improvements off of your income taxes on the years you made the expenditures? That would give you a rough accounting of the money you put in. If you did NOT take the expenses, I think that strengthens you significantly increasing your capital costs - and therefore reducing your gains realized at the sale.
But don't trust me on tax accounting! If you can't find an accountant that you feel is an expert on that topic, then it might be worth it to pay some hours to an actual tax attorney. Your place is beautiful, and I think it will sell for a ridiculous price. There may be a LOT of capital gains involved, and the proper treatment might be well worth the cost of a specialized attorney.
P.S. Since we have seen you back on Pond Boss, I hope that means your "ticker" is pumping blood at a satisfactory rate? If not, I am sure some of the aeration experts on the forum can send some ideas over to your cardiologist!
