What you are describing EXACTLY defines "Seller Financing".

A tear-down start is defined as a home built on a site where a previous structure or evidence of a previous structure was present before the new home was started.

You review the loan covenants before you purchase something and have the attorney take out or more highly define under which conditions the lender can call the note due.Lenders tend to use boiler plate language.

Personally I find their revenue share option interesting, though they have two  variations:  A traditional debt offering, where the borrower pays a predetermined principal and interest payment each month for the term of the loanA revenue share variation, where the borrower pays a predetermined percentage of their revenue each month until a defined multiple of the original investment is reached.

So if had the newly minted doctor and a defined 5 year time frame you wouldn't really need to buy for 50 cents on the dollar.  

Next I would reccomend define your area, and become comfortable analyzing deals to put in offers 

The first year I would take verbal requests for repairs, have loosely defined expectations for my tenant, all kinds of nonsense.

If you want to, checking with your zoning office on what defines the difference.

Just remember to build a team (say you know a thing or two about relying on others), go to your local REIA and network, define your buying criteria, and someday take some action!

While @Lane Kawaoka is right, it's important to remember that many who invest in 401Ks do so because the Defined Benefit plans that many of our parents were able to rely on in their retirement years are all but gone and we are having to rely on ourselves and own savings and investing efforts for funding our life in retirement.