Evasive, can you recommend trails for me? Arriving Friday afternoon, departing Monday morning. Intermediate riders who can handle increased difficulty if need be. Are there any must ride trails?
Yes, there are several. Unfortunately, the longer rides farther from town will still probably be snowed in, with the possible exception of Beartrap Gulch or Hanging Valley (the ones past York near the Vigilante Campground). But the South Hills can keep you entertained for a weekend without a problem.
The thing to remember is that the South Hills can be considered a series of ridges that finger out from town. You can add miles and trail segments to your ride as desired, so any ride suggestion could be added on to by going onto the next ridge. As thecreeper23 mentioned, the Mount Helena Ridge is the centerpiece of the South Hills trail system, and is a must-ride. The trailhead is about 6 miles south of town, up a gravel road. Once you get to the trailhead, it climbs another 800 feet or so, and then loses elevation gradually as it runs back north. It connects up to the Mount Helena city park, which has a bunch of trails, but honestly, it's pretty busy and not the best riding during peak hours. So, I'd recommend exiting the Ridge Trail at Show Me the Horse, which is a flowy (but old-school narrow) downhill that takes you back to the road. If you ride the Ridge twice, it's worth going all the way to the end, though. The views of the valley are pretty good. Also, when I ride the Horse, I usually ride south on the Ridge trail to get there.
Ride up the Wakina Sky road to Stairway to Heaven. This is one of our better sustained ridge rides, with pretty good views.
Climb Mount Ascension via the 2006 Trail and drop down Entertainment Trail, and then ride up the road towards Cox Lake. From there, you can climb to the top of Rodney Ridge, and come down Rent Money and drop into Orofino Gulch. From there, you could add another ridge or two, or head into town to the Blackfoot taproom.
This may be hard to take in on the screen, but makes sense with a map. There's a link to a live GIS map on the Bike Helena website (link in my signature). I also suggest stopping in The Garage on Jackson Street, and asking for ride advice. They have a huge map on the wall, and would be happy to steer you right. And stop into Bike Helena - tell Pat I sent you, and he'll probably give you a pair of socks as a souvenir. (And then go up the steps to Karmadillos for some fantastic New Mexico style BBQ fusion food.)
