Castle Mountain Trail is a one trailhead hiking trail, so you'll be backcountry backpacking it in and back out. This walk shouldn't take more than 2.5 hours, but of course some folks walk a bit slower and some a bit faster. Castle Mountain Trail is not that long but you should still bring some emergency supplies just in case something happens. Castle Mountain Trail is 3 miles long it's a short hiking trail. There's not much difference in elevation along Castle Mountain Trail which means the conditions are about the same from start to finish. The total elevation difference for Castle Mountain Trail is 591 feet which is lower than average.