Water is scarce along the ridge. A stream draining into Sardine Gulch crosses the trail 12.5 miles from Marble Pass, which is the only perennial water source I know of from the trail itself. There is access to several lakes from the ridge trail via connecting trails full of switchbacks. These lakes would be nice to visit but each one requires additional mileage and significant elevation loss and regain. Even if you hike to Twin Lakes, it is still about 10 miles from there to the stream.
The Elkhorn Crest is the highest elevation singletrack trail in eastern Oregon. You'll need a high clearance vehicle to drive to the trailhead or you can park as far up as you can go and hike from there.
There are lots of mountain goats on the Elkhorn Crest Trail and it is great as a multi-day out and back to Columbia Hill. If you're looking for something a little easier, there are a couple of shuttle options that can be pieced together. The first 5 miles to the Twin Lakes Trail intersection is a blast both out and back. From 5 miles to 8 miles is rocky and has significant exposure -- but it's fun and possible to hike it all. From 8 miles to 14 miles is great singletrack, there are some rocks but it's mostly a relatively fast downhill trail.