Featured on the Real cycling blogspot site as a day-ride (train, ride, train), but I think I might be tempted to convert it into a weekend trip.
http://realcycling.blogspot.com/2009/10/cycle-or-be-dammed-derbyshire.html

Includes link to some fab photos of the collapsed road of the old A625 round the side of Mam Tor featured as a ride in the ‘50 Quirky Bike Rides‘ book.

Definitely one for the list of ride ideas.