Disley - 10 miles (map): This route can be done in either direction. If time allows, add on Chinley Churn to liven things up a bit.
Gradbach - 16 miles (map): A challenging route around the popular walkers routes, near Lud's Church. Another nice one to do the other way round, but watch out for pedestrians (some grumpy!)
Manchester 100K (map): This is the route we took for the 2010 Christies Manchester 100K road ride.