owner wants to finance the renovation- need guidance on agreement

[Dan White]

The owner of a sfr bungalow in a good part of town wants to finance the renovation...or sell it outright.  I have my numbers where they need to be and she is ok with the current offer.  I would like to finance it with her because she is open to a very attractive annualized interest rate.  I have an idea on how to structure the repayment, however not sure exactly what would be best.  Can anyone elaborate on a good structure.  Keep in mind, she is older and this deal is "fun" for her.  She is open to whatever I have to offer.  I'm in a great spot, just need some guidance!  Thank you, Dan