Never much fun to go 4500 feet and for a view of fog! There are good views on a clear day along the ridge, but if it is foggy don't waste the extra effort. The scrambling is not bad here but the bushwhacking is not fun at all. You will get dirty on this mountain.
Mailbox Peak is a great conditioning hike... but traversing from that peak to Dirtybox Peak, as I did today by following the crest of the West Defiance Ridge, takes the conditioning to a whole new level. A lot of Class III scrambling on the ridgeline between the two peaks, but also a lot of views. I was the first person on Mailbox and Dirtybox today, and also the first person back to the parking area.