The entrance to Radiance is South of Austin and Oak Hill, off of FM1826.
You can reach 1826 from 290 (about a half mile South of the Y in Oak Hill), OR by taking Loop 1 (Mopac) to 45 and then to where it ends at 1826.
In both instances turn left (South) on 1826. The entrance to Radiance is approximately 10 miles from 290 and 5 miles from 45. Turn left on Crystal Hills Drive (Look for the Goldenwood sign). Follow Crystal Hills Drive for about 1 mile to Radiance.
