Yes, the tailwind last year was glorious after a couple of years with fairly brutal headwinds. As was said, most of the time in the spring, the wind is out of the southeast, so you are more likely to have a tailwind than a headwind...BUT...if you have a headwind, it will be because a front just went through, which means it will be strong. If the training series is too much, what you are doing is fine as long as you keep bumping the mileage up as you get closer to April. There are several good rides in the srping that you can sign up for individually for around $25-35 if you want some group ride experience prior to the MS150. Given that you came from somewhere with real hills, you may not really need it as much, but I would normally suggest that in late February and March you make an effort to get out further west and get some time riding in the hills. There is a ride in Chappell Hill in March I believe that is always well attended and supported that has lots of good rolling hills like you will find on the way to Austin.