That's potentially a garage converted into a rental unit that goes for $1250/mo.$1250*12/$30k = 50% CoC ROI.Are you CERTAIN that's not enough startup capital to get anything going with?

(i.e. minimal kitchen cabinets, no dishwasher, older doors are ok, painting vs replacing items, etc)

My 1000 sq ft 3bd/1.5 ba townhouse with garage in a slightly less attractive area rents for only $1050.  

If you can do it, $250 per door would be much better.

Also, I believe $900 is a “safe” rental price for the area D/FW unless in a bad neighborhood, a good area could command $100+ more each door.  

I will be able to knock on the door for the first time, later today!! 

You could rent out your current house if you buy another house to hack - and if your next house is a duplex (or more) that gives you 2+ doors right off the bat.

I was told here and there that renting out a SFH that has keyed entry bedroom door knobs (standard single cylinder and turn-button on the other side) is a fire hazard and against some kind of code or, if not, makes you liable for fire hazard dangers. 

We primarily do showers entirely fiberglass with nice doors.

My ultimate goal is to fund enough doors to either live off my R.E. and quit my job, or be able to do both and enjoy having the money necessary to walk away from a "real job" one day and do whatever I want.