Stephen-
Chapel Rd is plowed to within about 3 miles of the parking area. If you didn't want to deal with shuttles you could start/end here, with a side trip to spray falls. I think this is similar to what Ike did. I'll be skiing this route this sat, so I could give you any current info you need. The Chapel loop is the better cliff section, but fun can be had towards twelvemile as well. The cliffs taper off and twelvemile starts at coves campsite. It's kinda neat being inland behind a dune out of the wind.
Since you have 2 vehicles a shuttle is easy, and as mentioned you could start at Miners castle rd and come out at chapel road. Miners is plowed to within a few miles of the lake. You'd have to ask at the desk, I forget if it's 2 miles or 4 miles.

And just to wet your appetite the above pic is from a weekend trip to the tip of the Keweenaw. It was outstanding and something I'll post here next yr for others to join.
Dana