But how do I get financed once I quit my job and invest full time. 

I understand you have to pay in full by Cashier's checks.

Don't underestimate a house full of "stuff".

I would think that many or most full-time title/closing/escrow agents have at least some familiarity with seller financing on deals and can probably at least point you to someone that can help such as another investor or real estate attorney with experience structuring seller finance deals. 

Make sure to check out the Bigger Pockets Blog: https://www.biggerpockets.com/renewsblog/It is full of great information

I fill the tank before renting, then they keep it full and return it full before leaving?

Spencer Hsu I offer full real estate services in Indianapolis and believe I can assist you with your first duplex depending what your price point is.

The access road is basically an easement thru the front yard of the front 1/2 acre lot (which has State road frontage) as well as a full size ranch house on it.

If you're wondering why I'm going into the aviation field it's because it wasn't until after I signed up for the school I started researching real estate and reading books on it that I knew this is what I want to do full time hopefully before I'm 30.

This specific complex he has owned for more than 10 years because he told me he did a full gut rehab 10 years ago.