Betsy and I climbed Mounts Haeckel and Wallace in May 2013. Here is our itinerary for this three-day trip.
Day 1 (Sunday, May 26): Pack from the trailhead at Lake Sabrina (9,128 ft) to camp at Midnight Lake (10,988 ft). We go 7 miles in 5-1/2 hours.
Day 2 (Monday, May 27): Climb Mounts Haeckel (13,418 ft) and Wallace (13,377 ft). This takes us 12-1/2 hours roundtrip from camp. We make the first ascents of the year for both peaks!
Day 3 (Tuesday, May 28): Pack out 7 miles in 4 hours.
Photos and commentary follow.
Day 1: Sunday, May 26. We cross the dam for Lake Sabrina at the start of our pack in and are surprised to find hardly any water in the lake! 
This zoom photo shows our climbing objectives: Mount Haeckel in the center and Mount Wallace, the snow-topped peak to the left. 
Higher up the trail we see that the upper part of Lake Sabrina has some water, though the white face of the dam is exposed. 
Betsy crosses the outlet of Blue Lake on some logs. 
Next we get to Dingleberry Lake. Mount Haeckel is the snowy peak second from the left. 
We set up camp at Midnight Lake, which is just visible on the right. We had planned to go to Hungry Packer Lake but missed the trail junction in the snow. Two French climbers come down to our camp after failing to summit Mount Haeckel because they did not have ice axes.
Day 2: Monday, May 27. We wake up to a nearly full moon just before dawn. 
Half an hour later in the alpenglow we are ready to start our climb. 
After an hour of climbing we see the moon about to set behind the beautiful north face of Mount Haeckel. 
We get our first glimpse of the col that we will climb. It is the low point on the east ridge of Haeckel. 
Betsy climbs to the col. 
When we reach the col we see the imposing southeast face of Mount Haeckel. Our route goes down to the snow and then up the red-colored rock to the south ridge, which we follow to the summit. 
Betsy nears the summit of Haeckel. 
I reach the summit with Evolution Basin behind me to the northwest. 
Betsy signs the register. We make the first ascent of the year! 
I stand on top of Mount Haeckel. Mount Wallace is the prominent peak to the south. We descend to the frozen lake and then climb Wallace by going directly up the snow and rock face. 
Betsy nears the summit of Wallace. 
Betsy signs the register on top of Wallace. We again make the first ascent of the year. 
Mount Darwin is the massive peak behind Haeckel looking north from Wallace. After a cloud-free morning, storm clouds are approaching so we do not stay long up high. 
Betsy enjoys the snow that starts to fall after we cross the col on our way back to camp. 
A pile of rocks called a duck helps us find our way back in the falling snow.
Wayne Pfeiffer 