This sounds like a very long shot because it doesn't sound like she wants to sell unless she gets an outrageous price. She probably figures that she's going to lose most of it to capital gains taxes and she would. Try putting a land contract offer together showing her that selling it you over "X" number of years will actually net her more $ than selling it for more cash now. If done right it could by-pass her estate and probate.

Otherwise, she can't live forever...

Best of luck in the quest!

“My horn is full and my pouch is stocked with ball and patch. There is a new, sharp flint in my lock and my rifle and I are ready. It is sighted true and my eyes can still aim.”
Kaywoodie