You don't own it or have to worry about their mortgage unless you plan to exercise the option and buy the property.

As an educational exercise, I went to the courthouse and had them pull files of others who had petitioned for a tax deed.

Consider being a $60k-$120k worker for Amazon there and then run through the "drive till you qualify" exercise.

As an exercise, I think you should run your numbers with more conservative estImates and see if the deal still holds up.

The leases I had includes the option, no time limit, and no specific purchase price.So somewhere along the line, the tenant notifies you he will exercise his option to buy.As to why, plenty of reasons.

Just notify them, per the terms of the lease of course (ours is 30 days notice on month-to-month contracts), that you are exercising your option to terminate the lease. 

At the end of the term they exercise their option agreement, execute an agreement of purchase, get approved for a mortgage and take title of the property.Make sure you work with an experienced mortgage broker and lawyer to make sure you do things right for your area. 

It also has been quite an exercise in sweat equity, and learning to see everything from the guest point of view as opposed to our personal biases.Hang in there!

Define default and what happens if you go into default (ie. exercise their rights per the deed of trust which spells out how they take control or sell the property)This isn't everything but it's a start.

The way you have proposed would be the most costly way to do this exercise.