Tom's Canyon is a pretty great place to ride and this is a really great place to go visit. It's called The Water Jugs on the USGS Quad Maps, and appears to be a relatively popular spot to visit. The cache is hidden on the west side of the formation. If you go to the north side, you'll find a couple of relatively easy places to climb all the way to the top for stellar 360 degree views. It's a great place to visit, and terrific for kids.
The 4.0 Terrain Difficulty is primarily for the road coming in. It's a pretty great road in a lot of places, but there are a number of spots that are rough and washed out. We rode ATVs, and I generally recommend ATVs or UTVs, and I would rate it 2.5 to 3.0 for those vehicles. The road is more difficult for Jeeps or good 4WD pickups, and I'd give it more of a 4.0 rating for those vehicles.
Log Only BYOP - It's not a Micro, but it's tight, and it might be helpful to have tweezers to get the log out.
The cache is a small plastic Soda Bottle Blank with a log hidden at the base of a tree under a SPOR.

Additional Waypoints
P0AE96D - Off Loading Area
N 38° 59.760 W 108° 56.026
One of two potential off loading areas for ATV/UTVs
P1AE96D - Off Loading Area
N 38° 59.795 W 108° 56.218
One of two potential off loading areas for ATV/UTVs