This was our second visit. Last time we drove here and took the Forest Train, and it was awesome! A 90 minute round trip up into the mountains where the train uses switchbacks to gain elevation with a 15 minute stop at the top for photos and stretching.
This time, we took the Beach Train from Santa Cruz to Roaring Camp and back. A 45 minute ride each way with a one hour layover at Roaring Camp, where you can eat, shop, listen to music, pan for gold, watch the trains switch, and check out the camp. Entry to Roaring Camp is free but train rides aren't. Check their website for schedules and prices. I highly recommend a visit!