Nope, the transportation runs from a couple of the "official" hotels in Boise. I stayed at the Grove, which was across the square from another official hotel - can't remember the name of it. They used busses the first day for the meeting at the mill and then vans (driven by SFMI employees - equipment operators, etc.) for the trip up to the mines and Silver City.
We had a great meeting at the mill and they fed us very well, too. In spite of what some of the idiots over on idiot-hub said, there was NO alcohol served. I think somebody brought a 12 pack along on one of the vans on Saturday, but I had a beer at the neat old hotel in Silver City - plenty for me considering the altitude!
The van drivers were a font of information and, of course, they really knew the mountain because that's where they were working every day.
You could easily get by without a vehicle if you fly in and take the shuttle to-from the airport.