We stayed with Christine and Shaun over four days which coincided with the start of SXSW. Austin really surprised and delighted us and honestly the festival was our least favourite part!
The accommodation is a newly renovated, detached annex situated in the back garden so it feels like having your own place. The garden features a large tree providing shade and there's a hammock for snoozing/reading. The small kitchen is well equipped for a longer stay with everything you'd need to cook for yourself (that is if you can resist the abundance of food options nearby). The guesthouse has been recently and tastefully decorated, it feels clean and modern inside. There is A/C should you need it - we used it mainly for heat due to the stormy weather we had.
The neighbourhood itself is quiet and residential, however you are a short walk from South Congress Avenue which has numerous restaurants, shops and bars as well as a supermarket. There are loads of food trucks and vintage shops around here which make it a great place to hang out away from downtown. Austin's public transport isn't good so hire a bike, rent a car or use Fasten (Austin's Uber/Lyft equivalent).
Christine and Shaun were extremely generous and helpful, they provided loads of info and suggestions for places to go - all of the ones we made it too were great (although Rainey street was rather spoiled by SXSW). Definitely go to Barton Springs Pool - this is the jewel in Austin's crown.
Two more tips from us:
1. Check out Rodeo Austin for Mutton Bustin' (Google it) and Micro-Pig racing (plus the usual Rodeo stuff).
2. Head down to nearby Crux indoor climbing centre for Yoga, a well appointed gym and of course climbing.