This route description will begin from a campsite located near the crossing point of Vallecito Creek to access Sunlight Creek. For the backpack approach, you need to read the approaches from the trailhead that takes you over Hunchback Pass, down to Nebo Creek, across Rock Creek and then to the campsite at the Sunlight crossing. If climbing other 13ers in this area, you may want to consider climbing UN13,121 first (up the Sunlight drainage) because the view from its summit offers a great chance to scout out the route to P 2.
There is a pronounced avalanche chute/gully that sweeps down from the ridge just north of the P 2 summit. The bottom of this gully is a little difficult to locate because of trees at the lower end. It will be just a little south of the crossing site for Sunlight Creek and the campsites near there. These coordinates should help you identify the start: N 37° 37' 42.47" W 107° 32' 19.15". You'll need to walk from Vallecito Creek, back across the Vallecito trail to locate this start on the east side of the trail. Hike into the trees aiming for the chute/gully. The lowest point at which the trees open up in the chute is: N 37° 37' 37.79" W 107° 32' 10.53". You will encounter a lot of debris in the chute itself, so stay on the north side in the forest and head up for several hundred feet following game trails where they assist. Eventually you'll come to a section of the chute that widens out where you may want to enter it. There will still be fallen and uprooted trees, but fewer and more manageable now. A low ridge in the middle of the chute helps deflect debris to either side and you can hike more easily on the ridge crest through small aspens.
Looking up the chute, you'll see a tighter section with a likely waterfall (except later in the season). Exit the chute below that waterfall on the left and then re-enter the chute above it. The going is steep but mostly secure. Higher up, the chute appears to divide into two gullies with an island of trees in the middle. That's about 11,400 ft. We decided to follow the apparent path of least resistance by heading up the left fork, lured by greenish, tundra slopes amid the increasing rubble. Having scouted this route out from UN13,121 the previous day, we knew the right fork had snow and might not only require ice axe, but crampons or micro spikes, which we had not brought.
The two chutes/gullies become clearly divided by a rock rib. Continue in the left chute where after a few more hundred feet, you'll lose all tundra and will be hiking on steep boulder rubble. Higher up, this left hand chute begins to fragment into several minor gullies, defined by the angle of the metamorphic rock ledges. Several times we worked our way left somewhat in order to gain a higher ledge or ramp, but always working our way east and south, in the direction of the summit. As you near the north summit ridge, you'll find yourself scrambling at times to search out a route amid the ribs and boulders. This is where you'll most likely encounter some 3rd class work, which is not too exposed or insecure. Finally, gain the summit ridge and walk south over broken rubble and boulders to the summit, not too far away. There's some more minor scrambling, but no more serious obstacles.
The summit offers an expansive view of the numerous peaks all about. The most stunning view will be to the west, up the Sunlight drainage where the view of Jagged will mesmerize you. P 2 has a false summit to the south. Coming from that direction offers an interesting problem. Read about that approach on Former UN13,300 D (P3/13,279). To descend, you're best off just heading back the way you came for a knee-bashing descent back to the Sunlight/Vallecito camp.
Links to other information, routes & trip reports for this peak that may be helpful.