North East France by Motorhome

We are following the Tour de France as far as Belfort and then have a week to get back up to Calais with our twin-axle motorhome.  Very interesting to read the topic on twin-axles.  From Belfort we are going to a site outside Bussang for a few nights and then trek back up to Calais.  My question is, can anyone recommend anywhere to visit en route.  Our route will be a fairly direct one drawing a line from Bussang to Calais.  Troyes for example appears interesting but I'm not familiar with that corner of France having spent the last ten years visiting Brittany.  Any ideas would be most welcome.