Just finished my first hiking trail with the kids

Took my boys on a 4 mile hike last Saturday and they actually made it the whole way without complaining too much. My 6 year old was dragging by mile 3 but we bribed him with the promise of ice cream after. Trail was perfect difficulty level for their age. We're already planning the next one. Anyone have favorite kid-friendly trails they'd recommend? We're in the midwest so looking for stuff that's not too intense.