From the upper, 4WD trailhead, follow the Frenchman Creek Trail # 1457 WSW. In about 15 minutes of walking, the trail crosses to the south side of Frenchman Creek. In another 15 minutes, the trail intercepts the Colorado Trail #1776. Continue west on the Frenchman Creek Trail for another 1.6 miles to the end of the trees and a small pond and a marshy, willow-filled area at 11,940 ft. appx. In this area, both the Trails Illustrated map and the San Isabel Forest map show an older trail that heads out to the north. This is identified as #1458 and is called the South Pine Creek Trail. Hiking to this point will have been on an old roadbed and a well-used trail, since this is a popular access for both 14ers.
Hike north from the marsh/willows/pond, crossing the creek to the north side and then gaining about 200 feet in elevation. You should come across the aforementioned trail #1458 by then if unable to locate the start in the valley bottom. The trail is actually an old mining road. It swings west and crosses the NE ridge that connects Harvard with UN 13,374. There's little need to follow this trail to the ridge crossing, however, but staying on the trail will be less steep. At a point of your own choosing, depart the trail and head directly north to PT. 13,242, a false summit of UN 13,374. Though the hiking is steep, this is grassy, tundra terrain and easy to handle. Once on the flatter terrace surrounding Pt. 13,242, stroll across the tundra, embedded rocks and small rubble to the summit of UN 13,374. The last 200 feet are a rocky hill. Reaching the summit from the upper trailhead took us under 3.5 hours. The summit offers a great view of Columbia and Harvard, plus the more distant 14ers to the north or NW of Missouri, Belford & Oxford.
For a descent, return as you came. For the more ambitious, it's fairly easy to climb either or both 14ers from here. For us, we decided to re-climb Columbia. To do so, we hiked SW to the saddle between UN 13,374 and Harvard where the trail crosses into South Pine Creek. We descended from there straight south on some scree & tundra, losing about 600 feet to a flat, upper valley section of Frenchman Creek. Continue south across the head of the basin staying out of rocks as much as possible. Swing east to access a broader, mostly tundra-covered slope that leads south to the NE flank of Columbia, gaining about 500 feet on steeper terrain. There's a flater area at about 13,400 ft. Make the easy stroll across, then head SW to make the final, rocky ascent to the Columbia summit. The rocks are medium boulder size and tedious. This last 600 feet or so requires some scrambling over the boulders and close attention. Progress will be slow. For a descent, head back down through the boulders to the flatter area between 13,400 & 13,600 ft. On the east end of that flatter area is a scree gully that will make for a fast, easier descent. When it plays out, the terrain changes back to grassy tundra and you can rejoin the trail along Frenchman Creek.
Links to other information, routes & trip reports for this peak that may be helpful.