A note about the Eider Creek Trail. At the time we climbed T.0, this trail was not well known or used. In fact, from the switchback, the trail was actually an old, single-track road which we were able to drive up another .9 mile before being stopped by damage from an overflowing side stream. This reduced our elevation gain and mileage for the day. It appears that you can no longer drive up this road, so assume hiking will begin from the parking at the switchback.
From the trailhead, head generally north, hiking on the east side of Eider Creek through mostly lush, aspen forest. This trail is numbered #417. In a little over .3 mile, the trail will turn east and head up some switchbacks before turning back north again after another .25 mile. Continue hiking north until you intersect the Deep Creek Trail #418 in another 1.1 mile. Turn west (left) onto the Deep Creek trail. This is a well-defined trail & popular for mountain biking. In about a third of a mile, cross Eider Creek. (This may be more difficult early in the season. We had to cross on some fallen logs about 20 yards downstream.) Continue hiking west on the trail another quarter mile, climbing the switchbacks shown on the map and gaining a ridge. The trail drops a little into a shallow drainage, then gains another ridge. Leave the trail and hike north through timer here. There will be a brief time of bushwhacking.
Now the real work begins. If you head directly north through the timber, you should reach a clearing in about ten minutes. This will be the lower end of one of several shallow couloirs on the south face of Campbell. You may see evidence of elk in this area. Head up the mostly grassy gully to a rock outcrop which is a good place for a break and a view of the meadows now far below. Elevation appx. 11,100 ft. here. Continue up the same gully on diminishing grass and small rocks. There may be vague elk trails. After a few more hundred feet of gain, you may want to cross left over a rib or two to find another gully that continues up. We chose one with a snowbank lining one side and partially filled the gully. Continue to a cliff band at about 12,800 ft. The last few hundred feet will be on small chiprock that makes footing difficult. The peak designation of "T.0" may cause you to think here that it stands for "ticked off" because of the poor footing.
Clamber on up the loose rock and punch through the cliff band on the easiest route you can find. Intersect the SSE ridge of Campbell and continue to the unranked summit on rock that we call "dinner-plate talus." As you walk on the thin rock plates, it sounds like china breaking underfoot. Cross the summit of Campbell and head down NNE following the ridge on over to T.0. There will be about 235 feet of elevation loss to the saddle, then a final gain of 755 feet to the T.0 summit. The final ridge is of broken rock talus of various sizes - not fun, but not too difficult, either. You'll likely find a trail on this section. The summit affords a great view of the Dallas Peak west ridge and of the Wilsons to the SW and the entire range of peaks surrounding the Telluride Valley. This is one of the best views around. It's fun to look down on the airport and watch planes take off and land. Flying off the end of that runway must be something akin to taking off from an aircraft carrier. For the descent, return as you came, but also see the photos for another suggested descent path that would begin by heading east off the summit along the ridge that connects over to Dallas Peak.
Links to other information, routes & trip reports for this peak that may be helpful.