Bicycle Austin forum

Hello - I'm new to bicycle commuting. I have about a 20 mile commute from North Central Austin to Southwest Austin near the Veloway and Bowie High School. I'm interested in maybe biking to work once a week, but I've been having trouble determining an acceptable route. I wouldn't mind a combination of bus and bicycle. Its easy for me to get to Ladybird Lake, but if anyone has any suggestions for routes South of the lake I'll take them. Thanks for reading.