As you head up towards Jewel Basin hiking area, you'll notice a parking area to your right, this is the trailhead.
You'll be heading South East on the trail, gaining slight elevation the whole way. The trail is good singletrack with some more rocky areas and more loamy spots as well. A short while after starting out you'll notice a trail off to your left going up the hill, don't take this, keep going straight.
You'll eventually cross over Deer Creek, which is roughly halfway to Wolf Creek and a decent resting spot if you feel the need. The trail will continue to turn slightly to the left and the trees will open up revealing some good views. From there you're not at all far from Wolf Creek, however the biking does get more technical in nature and I sometimes will leave my bike to walk to Wolf Creek or I'll simply turn around at this point to enjoy the descent back down.
The Trail is roughly 10 miles total. It should be noted that this trail is outside of the Jewel Basin Hiking area which is why it is very much open to mountain bikers. Don't let people tell you otherwise! The Swan Lake Ranger District map
will confirm this and are available at the ranger office in Big Fork. Have Fun!