Paying your own health insurance, etc? 

You have several issues right now - I think your health and related debt should be prioritized - and work on RE second.

I would check out the financial health of the HOA before I purchased anymore condos in the building/complex if I were you.

So here are my questions -- Beyond keeping an eye on some generally available historical metrics such as avg rental prices, days-on-market and months inventory, how does one gauge the short term future health of a rental market?

We do life and health. 

I have hired property managers for the crappy ones, but that is a problem, too. The

Assuming you are investing relatively nearby to the town on your BP profile, long term real estate appreciation will probably be quite heavily tied to the long term health of Houston's energy sector.

For professional data, Reis is top in the industry, but since you are just starting out, that is probably above your budget (mine too). The

I need to make a living, and at 56, with my health issue, I simply don't feel that I'm "employable".

I'm going to start posting public health and real-estate advice merged together.