The ridgeline between the two peaks isn’t nearly as bad as it looks and the only significant scrambling is near the summits. As I was told about the Elk Range there is a lot of loose, crumbling rock that appears to be solid so checking the hand and foot holds was really important.
The standard route takes you back up and over Castle to safely descend the same route you came up.
14ers.com has some great pics and resources on this. There were a couple people butt sliding down the steep, loose gulley from the ridgeline to shave some time off but it looks pretty sketch.
The length of this hike really depends on how high up the road you can make it but with our start we clocked in at 3,900ft, 7.4 miles, and 7 hours (with a couple solid breaks).