This is one of my favorites; I have ridden it several times. To start off with I recommend heading up this trail counter-clockwise up Little Elbow trail. This trail is a fire road all the way which makes riding up the elevation easier. At Mt Romulus campground the trail starts to climb steeply until you hit the plateau. The view from this point is quite stunning and marks the start of the downhill sections. The first is a fast and steep ride down the road to Big Elbow trail. From there Big Elbow trail is single track over half the way back. There are few rocky sections but nothing too difficult. There is also some uphill on the way back but nothing to worry about. After a couple bridges the trail goes fast as its a fire road glide to the finish.
This trail also has some great stops on the way. You may consider a stay at Mt. Romulus campground for a hike up to Talus Lake. Tombstone Lake is also located a 25 minute hike off the plateau. I have stopped by for some fishing while riding this trail. From Tombstone Campground you can connect to Elbow Lake and the Sheep Trail.