I have a triplex that's fully rented out with long term tenants under contract now, and my intention is to now concentrate on sub 30k property's for cash flow.

I am thinking I might throw some concrete mix down the water main access hole to limit that source of water and then concentrate on the exterior.  

This is because I really like the idea of slow and steady wins the race and, I realize that I need to go a little bit slower in order to become steadier and to maintain my consistency long term. 

The problem is, I am having trouble narrowing down the particular part of DFW I want to concentrate my search.

Your late payments may have hurt your score, so concentrate on making on time payments every single time. 

Whats easier to maintain long run?

It's a small tight knit community so you have to conduct your business carefully to maintain relationships. 

I find taking some time between houses to concentrate on my home and family is not just good but for me a must!

Ventilation is necessary to maintain proper airflow through attic area.

Let them know that paying rent and maintaining the property MUST be their first priority -- you do not "work with" tenants.