Heavy rains in 2006 and 2008 saw the Carbon River surge and take out big chunks of the paved and gravel road that used to lead from the old Ranger Station to a car campground at Ipsut Creek. With limited resources, the Park Service debated whether to rebuild and relocate the road further away from the river or let nature take its course. They wisely chose the latter. You'll have time to appreciate the old growth trees that cars used to drive by at 35 m.p.h.
Start from the Carbon River Ranger Station and walk along Carbon River Road. The gain is so gradual that you'll barely notice it. But if the thought of walking eight miles roundtrip is daunting, consider biking! This is the only trail in the park that allows mountain bikes. Either way, you'll find the Chenuis Falls trailhead on the left after 3.5 miles of travel, complete with a picnic table. Facing the river, look left 45 degrees and you'll catch a glimpse of your destination. Continue along the bank until you see a ramp leading down to the river and your first of several footbridges. The Carbon has a habit of knocking these out when the waters rise during heavy rain and snowmelt. Check with the Park Service beforehand to make sure the footbridges are in place. Experienced hikers can get across without them, but it will likely result in soaked boots.
After crossing the first footbridge, look for a path over the rocks and sandbars that leads you to the next footbridge. Cairns are sometimes in place to mark the way. When you get to the other bank, follow the trail and the roar of rushing water to arrive just downstream of the falls. This is a rolling falls -- not as spectacular as a plunge falls, but no less pleasing to the ears. In late summer the conditions may be safe for careful wading. On your trip back look upstream for a view of Mt. Rainier as it peeks over its surrounding foothills.
Going further: About three miles from the parking lot you'll arrive at the trailhead for Ranger Falls/Green Lake. These are great destinations on their own, but if you'd like to add them to this hike you might consider saving them for the return trip, and make sure you have strength, water and daylight enough for another 3.5 miles and 1,150 feet of gain.