Wolf creek trail was a great straight shot to the falls
High Bluff's trail was also a nice straight shot, but in addition had more of an overlook to the Kettle River as well
Hell's Gate trail was close to the river and provided some fun and challenging rock climbing along the way to see Hell's Gate rapids--not recommended for small children, but we managed with a 4 and 7 year old.
"The Trego Nature Trail is a 3.5 mile round trip hike along the Namekagon River. It will take you through several forest habitats and offers occasional views of the Namekagon River. The diversity of life along the riverway is one of the best features of this trail. Whether you walk the whole trail or just a part, look for the many varieties of plants and animals. Wildlife species include deer, squirrels, fox, snowshoe hare, otters, muskrats, bobcats, and many species of birds. You may walk off the trail, but for your safety do not climb the steep banks of the river."