I thought about doing it fixed a couple of years ago but was also worried about the park in Bastrop. I took the bike on a campout in the park and tried it out. I run a 48x18 and had no problem with the short hills in the park. The hills are short enough that you can power up them and not long enough on the down side to be much of a problem. You have to controll your speed comming down or your cadence will be very high. I tried to keep the speed up but it gets painfull after a few of the hills.
It was the long slow hills that eventually kept me off the bike for the ride.