We went on Minnekhada trail with four kids 7 and under. Two older boys liked the changing path, enjoyed climbing on the rocks and logs, and loved throwing stones into the lake. The trail was OK for our 2.5 year old at first, but further on, the it became too challenging for him, so I would recommend having a carrier for such little ones.
All the adults enjoyed the trail. It is beautiful. The views of the lakes and the forest are fascinating! We didn't want to leave the park and will definitely be coming back many times.