River Meadows Park is a great place for a nice hike that isn't too far out of town. It's about 15 minutes outside of Arlington. There are several miles of trails to explore....some of them are along the river and some are through the meadows and forest. There are campsites and yurts available if you want to explore for a little longer.
River Meadows Park
Hiking River Meadows Park
River Meadows Park