Purchasing Derelict Home from Neighbor

[Ross Patterson]

My neighbor is 55 , single, and working two jobs to live in her 4 bedrooms 2 bath house.  She gets alimony but her ex has been delinquent recently.  The house in in disrepair.  At this point she can't even pay to have a huge tree removed that fell across her deck and yard. (and onto my fence).  She owes 170k on the home and it would be worth 850k when renovated.  How do I approach her to purchase the home?  What should I offer and what should be included in the offer?  My first thought is to offer her 450k and pay for her moving costs and fee to have a realtor find her a rental nearby. That puts almost 275k in her pocket which is a lot of money given her profession.  I think the rehab would cost roughtly 200k and take 12 months.  Thanks for the help!

Ross