Other fun high roads, closer to home, to consider (UK):

Old Military Road, Scottish Highlands: A83 (in the Cairngorms National Park), Blairgowrie to Aberdeen.
Wonderful remote scenery, amazing hills and bends.
 

Pass of the Cattle to Applecross, Scotland: Through the Applecross peninsula mountains to the sea.
Narrow, twisting, steep sections with fantastic scenery all around. Don’t rush; REQUIRES GREAT CARE!
 

Penrith in Cumbria to Haydon Bridge, Northumberland: A686. Traverses the Pennines ‘on the top of England’.
Spectacular moorland scenery, steep gradients and sweeping bends.
 

Capel Curig to Caernarfon (Caenarvon): A4086 – The Llanberis Pass.
Incorporates bends and gradients of varying intensity, and passes through beautiful scenery.
Great for the driver and passengers alike; take your time – savour the journey.