The Race Loop trail is around 8.5 miles in length. There is also an upper trail system incorporating a super D course, new Flow Trail and Jaws for jumps and berms. If you have the time and endurance, do the extra black loops, Upper and Reveille Peak, this is the Austin area's newest trail system just built by the Ridgeriders on a private ranch. Grand opening weekend is 12-13 February with race events. Trails open most weekends after that--when no race, the land access fee is 10$.
The trail is very rocky and much is large granite rock face--trail in these sections are painted ala Moab style. Super grippy and fun.
It is very tight in spots and is considered an advanced trail.
There is some smooth dirt here and there.
Don't leave your smart phone behind and do yourself a favor, download MTB Project or Trailforks in case you get lost.