Like to be abused? This is the trail for you! 15 miles of rough, rocky, steep Jeep trails (The 1st 3 miles are fire road and smooth) along Flume Creek Ridge with views to die for (and you might).
We do the ride as a shuttle: We leave a vehicle at the Sweetbriar Exit (#723) on I-5. Then drive up Castle Creek Road (along Castle Crags State Park) to the summit and we leave the 2nd car about a mile past where the road turns to dirt. Ride on down the main road, staying left where the right fork is signed to Mt. Shasta. About 1/4 to 1/2 mile later go right on the nice (unsigned) Twin Lakes Road. Continue another 2 1/2 miles staying left away from Twin Lakes (toward Tamarack Lake). The Tamarack road has a split section, the right side is rough and rock, the left less so, at the top of the right side is a jeep trail heading off north. Stay on this as it switchbacks up and over, to the south of Grey Rocks. Soon after, there's a fork in the road. Left goes steeply up and around a beautiful meadow with Pitcher Plants abounding. Push (just try to ride!) up this until you finally get to the 1st real (rough and steep) downhill. After this there's a climb (push), followed by a down, then up, then down, well, you get the picture. The trail keeps getting less and less used. Finally, you get on a logging road and it's downhill time for real (by then you'll be seeing views of I-5 seemingly 3000 feet straight below). Suddenly..., the road ends, just when you're too pooped to stand up straight. Turns out there was a landslide back in '97 and they abandoned the road. So, portage your bike along, following the flags. You'll feel like you're in a Borneo jungle or something. After about 100 tough yard, there's the road again. Stay on the main fire road until you return to the Sweetbriar exit (or take a wrong turn and come out on the Freeway in Castella, like we did). I suggest a dip in the river, followed by a beer (or vice versa).
The mai attraction of this ride are the views (Mt. Shasta over Castle Crags), the remoteness, and the fact that you survived.
Summary: Well, I wrote about the thing, so I guess I oughta review it. It's tough to rate, though. Scenery; definitely 5 stars, whatevers. The trail, I don't know. It's brutal. Steep (up and down), rough and rocky (up and down). The thing I don't like about it is that the uphills keep coming at you and they are mostly hikes (because of the rockiness). I had done it some years ago (back before full suspension!) so I thought I'd try it out again. Maybe in a year or two, when the pain memoies blur, I'll do it again. Next time I will have a camera, though.
Recommended Route: As in the description. The start depends upon where you shuttle to.
Other recommended trails in the same area: There's lots of logging road downhills in the area. We ride lots from Snowmman's hill (opposite the turn off for Shasta Ski Park) down to Soda Creek. Not singletrack, but fun. There's some good rides on Mt. Shasta. (Haven't ridden The Entertainer yet, but hear that's great.) The best singletrack in the area (Perfect Cycling Trail) is, unfortunately, illegal. There's a very scenic ride along the Upper McCloud River, too.