We had a great 5-night stay with Carol and Darrell over the Austin City Limits festival. Their hospitality was exceptional- great suggestions for things to do/places to eat, continental breakfast of cereal, fruit, pastries, coffee was available each morning and the house was charming and very clean.
We found it easy to get to the city centre of Austin via the 37 bus which has a stop about a 5-8 min walk from the house on Airport Blvd. You can travel for 24 hours on all Metro buses for $2.50 which we thought was great value, otherwise it's $1.25 for each single trip- we always made sure we had enough change with us as I don't think the drivers carry change for larger notes.
Definitely walk to The Omlettery for breakfast one day (10 min walk), it's a cute diner with the best omelettes we've ever had!
Would highly recommend Carols' place, you will certainly enjoy your stay! Felt like a home away from home :)