An excellent place to begin is the website, Handbook of Texas. After that you may want to search city and county webpages. Use the website State & Local Government on the Net to find official government pages. Many counties have genealogy organizations that publish historical information. Use the TXGen Web Project website to locate these organizations. Genealogy websites will often lead you to other information that you weren't aware of.
The library also has several books on Texas towns and counties. These books may give you more in-depth information than what you will find on a webpage. In addition to the MCC library, you may want to use the McLennan County or Baylor Libraries. You may borrow from these libraries using the Interlibrary Loan or TexShare programs.