Monumental Peak is sequenced with the lower Hancock (13,111) Peak. One-way mileage and elevation gain are measured from the summit of Hancock. Round-trip mileage and elevation gain assume completion of the entire sequence.
From the summit of Hancock Peak, proceed south along the ridge crest. At first, there is some fairly easy terrain with some tundra for a few hundred yards. Then the ridge passes into an area of rock ribs and gullies that drop off to the east. Things become progressively rocky here. As you ascend up to Van Wirt Mtn., the final approach will be on all rubble/talus. The day we did this hike, as explained on the Hancock Peak route description, it had snowed and the tedium of navigating wet, slippery rocks was taking a toll on us mentally. We decided that to avoid all the rock up to the summit of Van Wirt, it might be better to drop off on the east side of the ridge and contour south, below the summit of Van Wirt, then regain the ridge to Monumental further on. This was clearly a mistake in judgment. We dropped down a couloir on the east side of the ridge which was a little tricky, then found ourselves forced down much more than anticipated. This contour effort took us through just as much, if not more rock, all of which was wet and slickened by the snow. Then we still had to regain nearly 400 feet elevation back to a saddle on the south side of Van Wirt. Moral of this story - just go on over Van Wirt. At least you'll be tagging a "soft-count" summit, which we were unaware of at the time.
From the summit of Van Wirt, there's a good drop to a saddle followed by an ascent to the false summit of Monumental Peak. (13,254) Past the false summit, the terrain levels out some making handling all the rock a little more manageable. There is then one more saddle, followed by the final, rocky ascent to the summit of Monumental. All along this section, steady winds were blowing snow into our faces. Funny how what can be a fairly simple hike on a nice summer day can suddenly become something more like a winter expedition with life-threatening conditions. Huddle with all our spare clothing on, we finally gained this summit, but with the weather, there was no view to enjoy. If you climb this on a better day, there will be nice views down into the Middle Fork of the Arkansas.
For the return trip, our goal was to get off of the exposed ridge with the wind and snow, so after dropping back north to the first saddle, we headed down into a boulder-filled basin and contoured through the relentless boulders toward the NE ridge of Van Wirt. This also required traversing across a very steep slope to reach the ridge. We hit that ridge at about 12,600 ft. We assumed that things would get easier on the ridge, following it down to the NE, but we were wrong. We did follow the ridge all the way down to Chalk Creek Pass, but it would have been better to have dropped north off the ridge toward the upper Hancock Lake by way of a steep, rocky gully and get down to tundra. All along the NE ridge, we found ourselves scrambling over large-sized boulders on several occasions. Once you reach the pass, the rocky struggle is mostly over. Pick your poison. From the pass, just follow the trail back to the 4WD road and hike back to the trailhead.
Links to other information, routes & trip reports for this peak that may be helpful.