At 6:00 AM we started at Rd 9020 intersection with McClellan Butte trail 1015 -- there's room for a few vehicles just up the road. Trying for an early start on a long day of attempting McClellan, Mailbox and Si with no motorized vehicles in between, for a solstice epic. The trail was great where WTA work party had been! Some blowdowns around 2800-3000' then snow most of the way up, with numerous fairly steep gullies to traverse or ascend. Snow was stable on our way up, but ice axes a must. We used mountaineering boots, and took crampons but did not need. The rock at summit was dry and bare. Great views, and warm, sunny weather with a welcome SW breeze. Marmots in the rock. Snow was softening on the way down by 10 AM, with a stream running into one gully under the snow. Several short self-arrests among our party while going down. Early start recommended. From the 9020 road intersection, a switch for most of us to running shoes and hydration packs, then a jog down to X38, up road to the fire training center, and up an unofficial side trail to intersect the Mailbox Peak trail and to the peak. Lots of lupine, paintbrush, beargrass in bloom at the top, where we met 4 hikers with dogs Shadow and Mocha, who have been to many peaks with their lady who gives an Indian call from the top of each one. Trail is dry and decent shape. A snow patch at top for cooling tired muscles. Signed in at the mailbox, and went down the main trail. At the bottom we had bikes stashed, and rode west starting ~5 PM to Mt Si Road and to Little Si parking lot (~6 mi). Took Little Si trail to old Big Si Trail to the haystack, where half the party scrambled to the top while the other half donated blood to mosquitoes. A couple arrived to just enjoy the full moon. Back to the lot at 9:45 PM in the fading daylight, still warm. Total vertical gain ~10,000', loss ~11,000', and 30-32 miles. Tired and happy crew.