What's The Best Way To Structure This Deal?

I am a newbie looking for input :) I have the following potential deal and would like some tips on how I should present it to the seller. Property info: FSBO asking 199,900 - loan balance about 170,000 current monthly payment $1100. The comps I pulled are about $214k - 222k. Per the seller the property appraised for $230K. Seller Motivation info: Home is currently vacant. They want to sell quick in order to move closer to her Mother who is ill. She is retired. I have thought about suggesting a Lease To Purchase Contract and then in turn finding my own Tennat Buyer on a Lease to Purchase Contract. Since I am a newbie and this would be my first deal I am looking for input on what more experienced investors would do. What is the best way to present the deal? I am looking at "subject to" but then how would I provide a way for the seller to get the equity out? Thanks for your input.