It's open! All the way to Hawthorne, and riders can be found at all points along the trail.
The first few miles (from Boulware Springs) run through the Paynes Prairie State Preserve, and are only open from 8 am (presuming the rangers don't get their signals crossed and forget to open the gates) until dark. This section is clearly the best of the trail, as it winds up and down through a lush forest. If traveled at high speed, it can also be very hazardous, as there are tight, blind turns, some at the bottom of hills. Remember that this is a multi-use trail, and that you may encounter joggers, horses, roller bladers, deer, baby buggies, alligators, and kids on 12" bikes, especially on this section closest to Gainesville. Keep it down to at most 18 mph, and slow even more on the curves. Best yet, just take it easy the first few miles and enjoy the scenery.
Once out of the Prairie, the trail is more typical of a rail-trail, straight with good sight distances. As long as you slow when approaching other traffic, higher speeds can be maintained for most of the way to Hawthorne. Beware of the few crossings over limerock roads that are not paved; these can have buildups of sand that will dump the unwary road biker.