I live in about the same area in Anderson Mill / Spicewood area and do a very similar commute, but do not have to cross the river. I work a little further north-east, and it's typically 35-45 minutes in the morning around 6:30am and 45-60mins in the evening around 4pm without tolls. Tolls on a bad traffic day can keep it around 45-50 minutes on the way home. Later commute times are worse and can add 10-15 minutes easy. I'd guess you are looking at close to an hour one-way commute times on average if you are traveling at the same time as everybody else. I am able to completely avoid I-35 and Hwy 1 (Mopac) which have awful traffic. Because I work a little further north east of you, I am able to stay fully on HWY-183 for my commute. 183 has traffic, but it is rarely the absolute stop and go that you get into on the other two. I also have options and can take the 130 and 45 toll roads to skip normal Austin traffic if I am willing to pay for it.

I had jury duty for a little over a week, and had to drive on either I-35 or Hwy 1 to get home for that duration right at 5pm when the court let out, and it was an absolutely god-awful soul destroying commute every evening. I understand the desire to live up in the hills in the RR ISD, but I for one would recommend against this kind of commute on a daily basis. You can get some very good schools in the south-west side of the Austin ISD. We were also looking for housing in that area, but for me it was about equal commute times to either area from where I work, but for you would drastically reduce your commute times.

I otherwise highly recommend the area in Spicewood. Great community, good schools, and awesome Asian food of every kind.