First, congrats on finding a potential deal! Maybe try putting your info into the BP rental calculator and seeing what your potential ROI might be. You'll need to take educated guesses on insurance, operational and capital expenses, as well as vacancy.
Have you found your local real estate investing group? Often experts are willing to talk with you about deals, and sometimes even walk the property with you to talk about what it needs.
If you have a good sense of how much it will cost to fix up, you could maybe make them an offer as though they were the bank (owner financing) with how much you could put down and what interest you would pay them. Good luck!