The Vosges are about 4-5 hours from Calais, if you go through Luxembourg. There is non-toll motorway pretty much all the way. It’s a lot like Wales, hilly / small mountains and plenty of signed and not signed routes. We stayed at Gerardmer last year and had an awesome time – town big enough for family stuff, a lake, shops, sunshine, mountains, chair lift (small), good bus service around, a luge – what’s not to like!