There are so many nice semi-rural towns around Austin with folks who are real people.
But I noticed you've begun your search to the east and southeast of Austin.
Have you done any checking to the west in the hill country or around the Highland lakes? The area is a lot cooler in the summertime and the lakes are wonderful, even if you don't choose to live right on the water.
Look at Leander, Dripping Springs, Cedar Pk and Wimberley before you make up your mind.
I live in Cedar Park (NW of Austin), and while the traffic is terrible during the 5 hours deemed "rush hour," it's not bad to get to town any other time.
I'm hoping some big businesses in town will offer flex time for employees who commute.
I moved to central Texas from Washington state (90 miles north of Portland OR) in January 2000 and love it here.