I went to Shot Gun Creek on a Sunday morning in June and took time to get a good feel for the 3 separate trails the park has to offer: Tiki, Drury and Upper ShotGun. Each of the trail is around 2 miles in length. By combining them, I walked for about 5 and 1/4 miles (only did half of Tiki).
After paying my $3 day use fee, I parked between Shelter 1 and Shelter 2 just at the trailhead that gives the quickest access to the point where the 3 trails converge (followed the "Tiki / Harder" sign).
From there, I started with the Drury trail that climgs its way up to just below the ridgeline via a series of switchbacks. That climgs provides a nice -- but relative short, 3/4 miles workout to start with. The trail then slowly descends as it stays right under the ridgeline for about half a mile before descending back down to a bit above the creek level where it rejoins the Tiki trail. The Drury trail is well cut and maintained; just slightly overgrown as it descends on the SouthEast side of the loop.
The (upper) Tiki trail is essentially level and crosses several side streams through significantly more lush vegetation that the Drury trail. The trails follows the contours of the foothill before returning back to the Drury trailhead. This Tiki trail section is slightly under a mile in length.
From the 3-way junction (Drury/TIki/Upper Shotgun) I then conclude my hike via the 2 mile loop of the Upper Shotgun trail. The trail first goes generally and sightly up before descending back down through a small side canyon where it eventually turns back on itself for the return journey to the parking lot at Shelter 2. This return section offers view of and access to Shotgun creek in the last half mile or so before the parking lot. While it is true that the road is just on the other side of the creek, and therefore takes a bit of the "great outdoors" experience away... it is nevertheless very nice to follow the water after about 5 miles of walking under a relatively dense forest canopy with basically no open views.
Even if views are conspicuously absent on the hike, the forest is nice enough to be worth the 2, 4 or 6 miles you can opt for depending on time, shape and interest.
Overall a good option when a location near Eugene/Springfield is what you're looking for.
More accurately Upper Shotgun Creek Trail.
There are two trails, each roughly two miles long, starting at the Shotgun Creek recreation area. Upper Shotgun Creek is a 2.4-mile loop with a few hundred feet of elevation gain (mostly forest floor). The trail is easy and fairly well-maintained, crossing over a few trickling brooks but only muddy in one or two spots. You won't find sweeping vistas or destination views, but the area is lush with ferns and moss and some old-growth forest. The trail's only major downside is that there is an OHV park nearby, so the area lives up to its name with the sound of frequent gunshots nearby. Also, the last half-mile or so runs parallel to the road, with the creek between.