Potential Sale, How to Best Structure

[Char Prado]

Scenario with as much info I could get as possible.

5br 4ba rambler (1 level) SFH with carport

Owner's mother passed and she still has husband to care for.  She's listed her house twice but hasn't sold.  Needs cosmetic upgrades and a restructure of 3 bedrooms that don't have doors leading into next room/enter through hallway and exit the other side into hallway.  2408 sq ft. 

 Owner still has a mortgage ($2100)  though  I don't know what her final balance is.  I've mainly been doing wholesale deals and this will be our personal home and she has agreed to sell to us using an attorney.  We could pay $5000 down and $3000 monthly for no specified time period but maybe in 10 yrs we would get a mortgage.  She doesn't need the money to move.  We've offered to pack and move her :)  She's asking $489900 which is retail and fine with us.  

How is the best way to structure the deal so both parties are protected and we can get the best benefits of home ownership?   All I told her is she'd be the bank and the financial terms I mentioned above and she agreed.  All inputs appreciated!!!  Thanks