I was part of a large group that did this hike in July. The main body left the trailhead around 8AM and got back around 6 PM. (I actually jogged the first few miles and caught up at the first major stream crossing, having left the trailhead an hour or so after the main group).
It's eighteen miles round trip, so for planning purposes, budget at least nine hours unless you're comfortable with the idea of forcing your pace all day long. It's a pretty long hike, so plan on slowing down for water breaks and lunch, plus two significant water crossings. Ten hours ain't bad, though a fast hiker can surely do better.
Much of the trail is dead flat and very wide, so if you do like to go fast this is a good hike to push your pace on.
I don't think the bushwhack would save you any time, though I've never tried it myself.