Better yet, don't do it unless other people are pretty confident in your fitness. Some wet/muddy creek crossings, but otherwise dry. Super loose after second intersection. This is a shuttle access downhill trail that is suitable for all ages and multiple different bike styles- although best suited for all mountain, dirtjumper or full on DH bikes. Greens Lick is a machine built trail designed by Trail Dynamics as a demonstration trail showing the forest service how eroded road beds could be converted to sustainable trail.
From Lake Imaging Road it is a steady but not steep climb to the high point just before the intersection with Hooker Creek Trail. The main bike trail is about 18KM long with a gentle -5% grade. The final chute has a perfect natural double jump in it to give the extra bit of gnar to make you feel like a badass. Removable by hand saw. The upper half is more technical with lots of rocks and a step up onto a boulder.
Highly advise starting from the Mt. There will be some short dismount sections for most riders, but overall, the trail is fast and fun. Technically you can go both directions but everyone typically starts from Guardsman and either drops down Desolation or continues to Mill Canyon or Ridgeline Connector. Parking at the bottom is near mile 12 of Palmer Fishhook Road, while the top of the trailhead starts near mile 16 of Palmer Fishhook Road. The ending is real rutted out, so be careful not to lock up your tire and make it worse.