I since contacted a real estate attorney and has been advised that I can assert myself and enter the property if I have keys or get a locksmith. 

If it's under 500 in value and then trash generally people just re-key without eviction.

Anyone have a referral for a reasonable but dependable locksmith in the Houston TX area?

No one wants to be greeted by an angry tenant waiting with firearms.At the appointed time, we come with a locksmith, two moving men and their moving van and us in our protective gear (work clothes, gloves, N95 face mask, and eye protection) and boxes and bring construction quality plastic bags.

We now prefer to use Kwikset's newer system of re-keying a lock seen here:http://www.kwikset.com/SmartSecurity/Re-Key-Technology.aspxSave's us landlords tons of coin now in changing over locks when a new tenant moves in.

They're about $30-40/set upfront, but then there is no marginal cost to re-key in the future.

The thing I do  now is have the locks re-keyed after the move-out.  

Save extra funds, find a good, quick locksmith to re-key locks asap, start a relationship with a real estate, owner-tenant lawyer who can manage the legal situations, understand local laws and what would and would not apply in varied cases, have a stable of vendors and contractors who can do any and all work needed to return the property to desired condition, start a folder with necessary paperwork for court filings, connect with property managers or other owners who can help with information, be prepared to document EVERYTHING, etc. 

I always hope to rent the home and only have three days of vacancy for cleaning and re-keying so I start showings 30 days before lease is up.

Have your locksmith ready to re-key right away.