Some good up and down climbs on the ridge trail. The second half (think we came back on the Wildcat Creek trail) wasn't great, it's basically a road. Next time I would go out and back on the ridge trail to do the climbs twice. Better workout and better scenery. As other reviewers noted, the ridge trail is very exposed and not much shade so early is best and bring lots of water. The ~7 mile loop took us ~3.5 hours.
Trails were decent for going through cow pastures. The scenery was ok, you could see the Golden Gate Bridge and the Richmond San Rafael Bridge and also see Richmond and El Sobrante. However it did have some really good hills which worked the legs real good. I gave it four stars for a good work out but 2.5 for the scenic view.
I hiked out from Wildcat Creek Trail, up over the Belgum Trail, following the San Pablo Ridge Trail, then the Nimitz way, down the Havey Canyon Trail, back up to the Mezue Trail and back. Approx 7 - 8 miles of roundtrip and gorgeous scenery and pleasant temperature this time of year.
I had a pleasant experience hiking on this trail. Staying with the main trail and it was wide and relatively smooth. There were some great views and we could see as far as the Golden Gate Bridge. The weather was nice with clouds blocking the autumn sun and cool breeze was on our face. During the summer it could be hot up on the ridge. The loop is 6 miles long and it is bit too long for the beginner.