Austin should bee a great place to try this. There are some good size hills to deal with in areas, but downtown is relatively flat and the wind is usually much less.
If you have even one or two cyclists on the same road and within sight it seems cars treat you decent enough, riding together and you almost get respected...alone and you better be very aware and ready for some harassment. Even 100 additional regular riders should help everyone out. More regular looking riders might help too...
I see the heat of summer being a problem for many, I am not looking forward to it myself. Already had one heat stroke outside of cycling and fell close while riding this last summer on one of the worst days.