Here are some links to our favorite places to ride so far:
The ride through the dunes to the beach is a great warm up for the horses and on a day that's hot inland, that sea breeze is very welcome. Parking is great, easy to pull into and out of with a trailer and easy access to the trail head.
Shiloh Ranch Regional Park
Another great trail that has a nice steady uphill to warm up the horses. Not too rocky, though a bit here and there. It's a good climb up and then a really great loop back on the Pond trail, I think, that brings you back level and in the shade.
A great beginning ride, or just a quickie, is Riverfront Regional Park in between Forestville and Windsor on Eastside Road. It's a nice flat loop with good parking for trailers on the road in.
Armstrong Woods has a more challenging trail, but it's also nice when it's really hot inland because you're nestled under redwoods for a lot of the ride. It's strenuous and a little technically difficult in some places. When we went there, one of the women in the information booth told us she didn't take her horses on it, but Lena and Doc both did fine even on the stairs and steeper parts of the trail. Parking can be tricky - go early if you want to park in the free lot and try to get one of the pull-through spots. Otherwise, it's worth it to pay the fee and pull into the picnic area so you have ample room for the trailer.