Hey Uforgot, there's actually a book of maps for road rides in TX. A friend gave me a copy a while ago - it's called best bike rides Texas. There are several maps for rides in Hill County. Unfortunately it's hardcopy so quite hard to attach to a post on the forum but if it helps I could fax them.
You can also look up some of the cycling clubs in the Austin/San Antonio area - I'm sure some of them will have their regular ride maps posted on the website. Most of the clubs in our Houston area have pdf copies of all their ride maps on the internet...
Good luck and enjoy your vacation in Texas!