I have created a spreadsheet for quick analysis (with the 2% rule, 12% cash on cash, total ROI of 15% per year, etc) and have just been analyzing any Zillow deals that pop up.

Know the lenders requirements for the loan types you will need.For instance you may find you need to have liquid cash of 9 Months P&I and 100% of the loan amount as your personal net worth in order to avoid personal guarantees on the loan, and your retirement accounts may not count towards your liquidity.Know the requirements of the loan products for the apartments you want to buy.There are no books for that, that I know of--just lenders info.Because without that all else is just scholastic exercise.Good Luck!

Current plan is to take out an equity loan on the property (tax rolls have it at ~$300k) and use some additional cash to build 4 units, then refi, then build additional units until we have ~20 doors on the property. 

Texas, and especially the San Antonio area, has some great opportunities for real estate investment, whether you're looking at single-family rentals, multifamily, or even new construction.I'm primarily focused on the Indianapolis market, working with investors on new build duplexes that offer solid returns and long-term potential.

I have a long history in real estate first being licensed in 2005, then went into financing, back to real estate all while owning my own hospitality business for over 12 years as a single mom of two, building it from the ground up.

They are out on the lake all day, on the beach or riding the 72 mile long bike trail.

When you go to renew the lease, the renewal will spell out the renewal terms.  

I am considering buying an investment property in cash in a very nice development. 

And also, what about buying in an area that allows for non-owner occupied STRs, so you can Airbnb or short-term rent the place when you move out?

Real estate investing is a long game.I wish you all the best.