This trail can be strenuous - not because of the elevation gain or mileage, but because you'll be walking in sand for a large portion of the hike along Eagle Creek, Pine, and Ridge Fire Road. Aside from the sand, it's a beautiful hike, with areas to play in the river if you wish. You can see some plants starting to take over the burned area near the observation deck, which makes for a pretty nice scene of green plants against the otherwise bleak black landscape. There is a large grove of giant redwoods near the entrance of the park if you're looking for just a quick peek into what the park has to offer.
Day use parking fee is $10, but the lot tends to fill up by noon on weekends.
Henry Cowell State Park is right next door to Roaring Camp Railroad, which is a bustling little village with food options and a small amount of amusement for visitors. You can take the historic steam trains down to the Santa Cruz Beach Boardwalk and back after you're done with the hike.