Cedar Breaks is west of Georgetown and is a Corp of Engineers park. 50 amp, water but no sewer. Nice quiet place, but usually full on weekends.
Unlike Hal, I will drive a ways to avoid Austin. A recent show on TV listed Austin as the #3 most gridlocked city in the USA. Los Angles was #1.
Here is the link to the 130 Tool Road calculator.
Toll Calculator | SH130