Hidden Falls lies about 5½ miles along the Tarbell Trail, starting from the northern-most trailhead, which sits by an isolated parking lot. If it’s a busy day there may be one or two other cars sitting along the Washington DNR’s signature-style pit toilet. Other than that your interactions with others might be limited to the sight of a logging company’s trucks passing through in the summer.
Bell’s Mountain Trail is one of my favorite hikes in the Yacolt Burn State Forest for taking people who have little to no hiking experience. The trail is open to foot, bike (non-motorized), and horse traffic, so you’ll see plenty of different types of people here. I have never seen a horse on Bell’s Mountain trail, but keep an eye out. Also watch out for the adventurous trail runner making the attempt upwards and the daredevil of a mountain biker coming down. Typically the regulars of this trail, and the surrounding ones, are super nice and welcoming.
The trail itself isn’t too difficult, you get most of the elevation gain out of the way within the first mile after the junction, with an average grade of 3.1%. Take it easy and slow, there is certainly no rush to get to the top. The views through the border of the Yacolt Burn State Forest are amazing.