We really enjoyed our autumn hike at Munn Woods in Ames today. We started at Emma McCarthy Lee Park and roughly followed an AllTrails map to the Hickory Drive trailhead which is near Tahira & Labh Hira Park. My kids loved that there were playgrounds at each end of our hike, which was 1 mile each way.
If you start at Emma McCarthy Lee Park, there's a parking area right next to the trailhead. Head toward the lower park, then park in the first area on the right. The trail starts to the right of the bench and kiosk. It's fairly well marked with Stay on Trail signs and Private Property signs, but there were a couple spots that we were uncertain which way to go.