Hi Craig
I have travelled the France, Belguim, Luxembourg, France route Switzerland/Italy in 2006 and 2007. I originally got this route from Caravan forums. My only variation is that I travel east on the N66, through the Ballon de Vosges (sp?) which is a very scenic and very towable N road through these mountains. This route is excellent quality FREE autoroutes, apart from N66 stretch, the Swiss border, We had a very pleasant couple of days at Camping Des Acasias in Cernay enroute.
I would only make 2 comments. Firstly in 2006 I crossed into Switzerland from France which meant that I had to travel through the centre of Basle - a lot of roadworks. In 2007 I took advice gleaned from caravan websites and crossed the Rhine into Germany just before entering Switzerland. That meant I avoided the centre of Basle - a BIG IMPROVEMENT.
Secondly in 2007 on the way home, after a breakdown, we had a, Red Pennant, provided hire tow car which was a little underpowered for our 'van and so I opted for the Brenner motorway route from Italy into Austria and then Germany. I found that, although free, the German autobahns were not such good roads as the French autoroutes and I encountered a lot of roadworks.
I hope this is some help. Have a good holiday.
Tim