From Provo:

Follow US-189 (Provo Canyon) towards Heber City.
Turn RIGHT onto W 3000 S. If you reach W 2400 S you've gone about 0.7 miles too far
Turn RIGHT onto S BIG HOLLOW RD.S BIG HOLLOW RD is 0.3 miles past S 1000 W
Follow Big Hollow Road until it comes to a T.  Turn right (west) and follow that road until the end which is the shooting range.

From SLC:

Merge onto I-80 E towards Heber City through Parleys Canyon.
Take the US-40 E exit, EXIT 146, toward HEBER/VERNAL.
Merge onto US-40 E toward HEBER/VERNAL
Turn SLIGHT RIGHT onto US-189. S
Turn Left onto W 3000 S. If you reach W 2400 S you've gone about 0.7 miles too far
Turn RIGHT onto S BIG HOLLOW RD.S BIG HOLLOW RD is 0.3 miles past S 1000 W
Follow Big Hollow Road until it comes to a T.  Turn right (west) and follow that road until the end which is the shooting range.