The trailhead is at the back side of the parking lot at Batsto Village. It is well marked as is the trail itself (orange blazes and brown wood mileage signs). The Orange Trail is the longest loop in a series of stacked loops. This trail, as well as the other trails (with the exception of the Green Trail) is 99% singletrack with little change in elevation. All of the trails are well suited to hardtails and singlespeeds. There are lots of twists and turns and a few log overs.
The distance and remoteness of the Orange Trail increase the difficulty. I prefer going counter-clockwise. That way you get the real twisty/slow sections out of the way first. The second half is more open and you can get some speed and flow going. Sandy soil makes this a good place to ride when everything else is too wet.