This crack system between Post Moderate and Grape Ape is one of the older Diablo routes.
Up easy corner to undercling/lieback left (5.9, good pro here). Continue up a more low angle shallow corner crack system with just seams (no cracks) and very little pro (5.8- don't fall) until the next blocky roofs. Turning these blocky overhangs (good pro- bigger cams) is the fun crux of the route. Reach a 2-bolt anchor. Rappel from here, or continue up the upper half of Post Moderate.
Since the lower half of the fully-bolted Post Moderate can be climbed to reach the anchor, most traffic on Highly Caffenated is from people toproping it these days.
Location
Climb 5 on the beta photo. The excellent original online guide might also be of help. Crack system between Post Moderate and Grape Ape. Starts just left of the post.
One 60m rope works. A 50m rope probably doesn't reach, but might?
Protection
1 set cams to 3", 1 set nuts, micros potentially useful. 2 bolt anchor equipped for rappeling at the top.
This route was established by some combination of Mark Thomas, Tom Wezwick, Karl Kiser, and Chris Kessler, all of whom worked together on several routes at Diablo and in particular on the Winter Wall.