The lower park trails are pretty well marked, but very flat and boring. If you're in decent shape, you have to go through the horse gate and up into the hills to appreciate this area. Once you go through the gate, the signs disappear, so you're on your own. The grades are pretty tough, partially because they're mostly loose gravel. I'd give it three stars, but the views from up in the hills are pretty amazing. Almost zero shade, so be prepared on hot days. Recommend insect spray for the biting flies in the warm months.
This hike was very hard to start and many parts of the trail were very steep with a lot of loose gravel. I'm in shape, even fit, and I was sore and tired when I was done hiking today. The trail is not marked at all, which is kind of frustrating, but I had great internet service throughout so I pulled up this app multiple times to see where I was. There are a lot of trails throughout so it's easy to switch from one to the other. The views are amazing and the hike is worth it, but it's definitely a challenge.
There were just a bunch of random trails so I picked one and it ended up being about a mile. I was hoping for a longer trail. Also, it was really flat. It would have been nice if there were signs telling what's what. Or maybe I just didn't see them. Watch out for snakes.
Hidden Valley Park has five major trails with lengths ranging from 0.3 to 2.4 miles and typical grades ranging from 3.5 to 10.8%. The Highland loop is the most difficult, but it also has the best scenery and views. The Highland loop has sections of narrow trail with loose soil on steep cross slopes. I was glad I had my hiking poles.