Red Bluff is one of my favorite blocks of Austin, with semi-secret views of Town Lake. Our first three stops were on this street: a recording studio that used to be an artist's studio with amazing natural light; The Barn, with several artists, including this cut wood sculpture; Dragonfly House has an amazing water view from the back garden.
ARTPOST is a collection of studios. My favorites were the big oxidized metal sculptures and a silver-leafed large metal tree sculpture (unfortunately I don't know the names of the artists). Also, we stopped in one of the studio spaces and I was happy to discover it belonged to Katy Horan, though she was not in at the time. I have one of her prints from Tiny Showcase and had no idea that she lived in Austin.
Fisterra Studio and Caroline Wright are two house/studio combos that are really beautiful, fun places to visit. Both display the work of the owner and a couple other artists, and I've really been drawn to Wright's work since I saw it on the tour a couple of years ago. And I love her studio with that giant easel on casters. These photos don't do justice to the enviable decor of either place, so add them your list if you're in Austin.
And on a non-art East side note, there's a new-to-me food trailer lot on E 6th a couple blocks from I-35 which has awesomely decorated/themed trailers and menus.
For more ideas, the Austinist recommendations. And the official E.A.S.T. site. More photos here.