From Middle Fork Rd trailhead via the new trail to the summit of Mailbox Peak, then back down (also on the new trail).
Marcy carried an InReach tracker. 1h51m58s to the top.
"Beautiful trail! Love the view of Mount Rainier from up high. That last bit to the top is a doozy. The mailbox is very cool :) My ascent time on the new trail was 1:51:58. Spent 7 minutes at the summit. I took it easy on the descent (careful on the rocks), roundtrip time of 3:28:30. An excellent route, thanks for the inspiration."