Matt - looks like Chamonix is going to be the first mountain area you get to! Everywhere I was going to suggest would actually take you way too far south, the Greece/Macedonia/Albania area is fantastic, roads would be open and would be right up your street, but its hardly on the way!
You could try going through the Pfalz and Frakenjura in Germany, dropping into the Czech then heading back west through Austria and Switzerland. Some of the higher passes will be closed but there will always be a route through. Might mean a lot of tunnels though!