Mescalito, Pine Creek Canyon
About the Climb
Y2K is a very cool route and although it is rated 5.10a/b, a confident 5.8-5.9 leader should not have too much trouble on it. There is only 1 crux 5.10a section: a roof move on the first pitch that can easily be aided if you have to. The crux is protected by a bolt just where you want it, and is surpassed by using key edges and footholds. Otherwise, the bottom pitches offer enjoyable and sustained 5.8-5.9 climbing. The 3rd pitch is less consistent, but the last pitch has a superb left facing corner, starting easy but getting steeper and demanding tricky and thin pro near the top (5.9).
Because Y2K is a relatively short route, you can easily combine it with another route. Luckily for you, there are many classic climbs only 10-15 minutes away. Most of these classics are at a slightly lower grade, but still good fun.
The closest route is Dark Shadows (5.8) which is only a few hundred yards North of Y2K. Dark Shadows climbs an amazing varnished corner in a very scenic setting. If you haven't ticked it off yet, you should definitely go for it. The climb can be very busy, so your best bet is to climb Y2K first, and hope the line for Dark Shadows is gone by then.
At a lower grade, you could go for Birdland (5.7+) or Rawlpindi (5.7). Both are great climbs on the left side of the Brass wall. However, these two climbs can make for a killer full day by combining them together, so it would almost be a pity to do one of them after or before Y2K. The Brass Wall also has many great single pitch routes, which can be climbed to fill your day.
The Southern end of the Mescalito buttress is home to Cat in the Hat (5.6) and Cookie Monster (5.7). Cat in the Hat is the most climbed classic of its grade in Red Rocks, so it can be busy. You can avoid the potential crowds at the start by climbing Cookie Monster, which ascends an amazing corner filled with jugs and huecos. From the top of Cookie Monster keep going up the upper, and best pitches of Cat in the Hat.
Crimson Chrysalis (5.8) in Juniper Canyon is a great and popular classic with sustained 5.8 face climbing. However, Crimson Chrysalis has 8 pitches, so it takes a little longer to get to the top. All the belays are bolted, so retreat is easy. Alternatively, Refried Brains (5.9) in Black Velvet Canyon also offers sustained 5.8-5.9 climbing, but the wonderful crux pitch is more crack than face climbing.
If you are looking for something a little harder, try Sour Mash (5.10a) in Black Velvet Canyon, which has several sustained 5.10a pitches. All the hard pitches are very well bolted, so it's not very committing. Another step up is Dream of Wild Turkeys (5.10a) also in Black Velvet Canyon, a slightly harder 5.10a.