Take a walk along the Coburg Ridge. A trail through older growth trees opens up to a meadow with views of Coburg, Eugene and the Willamette Valley (or you might get treated to a nice view of light gray fog). This is one of my favorite close-to-town hiking spots.
There are several trails up to the top. If you take the shortest route, it's 1.5 miles round trip, 420 ft. elevation gain round trip. Terrain rating is due to the steep trail - no climbing necessary. No poison oak exposure if you stay on the trail.
Check out the triangulation benchmark just south of GZ (you can see the witness post from GZ). QE1733
SPOILER ALERT: If you'd like driving directions, parking coords and/or trail directions/map, take a look at the gallery (see links below). If you'd prefer to figure it out on your own, definitely don't look at the gallery.