Cave Route provides the most straightforward approach to the Upper Terrace on Bookmark Pinnacle, offering a modest trad climb set against the rugged backdrop of Lumpy Ridge in Estes Park Valley. The journey begins with a scramble up the northern descent gully, where the terrain quickly shifts from loose scree to solid rock, signaling that roping up becomes necessary. This route demands careful footwork and steady commitment as you ascend to the base of two defining cracks on the north face of the Upper Terrace—one a hand crack and the other a challenging offwidth.

The hand crack leans into a gritty, moderately featured chimney system that requires precise jamming technique. Climbers should prepare for an unsettling encounter with small bushes and occasional guano deposits, adding a raw, untamed feel to the climb. This section is short but can become awkward if you're unprepared for the natural obstacles, so focus on controlled movement and avoid unnecessary reachy moves.

Once atop the Upper Terrace, you have two viable options. Extending the adventure by climbing the summit blade as a second pitch rewards you with more refined moves and a satisfying finish. For those who prefer a quicker exit, rappelling from the anchors on Time Machine offers a straightforward retreat, though rappelling directly from the chimney’s chockstone is strongly discouraged due to instability and potential hazards.

The length of this route is about 100 feet, typically done in one pitch with the possibility of adding a second if extending to the summit blade. Protection should include a standard trad rack capable of handling up to 3-inch pieces, with attention paid to careful gear placement given the nature of the cracks. The route’s 5.8 rating places it on the easier end of the trad spectrum here, but its awkwardness and the natural vegetation ensure that it stays interesting.

Approach conditions are manageable with a roughly 20-30 minute hike from trailheads near Estes Park, crossing forested slopes dotted with piñon and juniper before reaching the base of Bookmark Pinnacle. The high-elevation setting can bring afternoon winds and cooler temperatures, so packing layers and hydrating thoroughly is wise. Start early to avoid the heat and afternoon storms common in Colorado’s soaring mountain environment.

Cave Route isn't about flawless rock or slick moves—it’s a straightforward, practical way to gain the Upper Terrace while experiencing a slice of Lumpy Ridge’s gritty texture. It strikes a balance for climbers who want moderate technical challenge without the demands of long approaches or intense crack climbing. Just be prepared for the natural quirks and keep a cautious eye on anchoring and descent plans. This is the kind of climb that rewards patience and clear planning, unlocking a quiet corner of one of Colorado’s most storied climbing areas.