Hi RoadRanger,
It will take you 2 long days to get there. Im retired now and am always over the pond in our campervan. First of you will need a toll sticker for Swiss its about £38 it last a year. You can get them on line from a German Company “TOLL TICKETS” you have to stick it in the top middle of the windscreen so the cameras pick it up you can only stick these on once so get it right first time. The Austrian toll sticker you can get for a few days and its a lot cheaper. If you go the route we took down that way a couplke of years ago We left Calais doubled back up to Belgium - Luxembourg - France overnight at an Aire in Charmes 8 euros with EHU don’t forget your polarity change electric lead and the euro plug lead for Swiss. Then down to Basle haed for Como- Milan - Lake Guarda.
If you want anymore info PM me. the Swiss toll sticker is that price for up to 3.5 tons if you are opver that silly money, and if you pay at the border you will; be paying more than TOLL TICKETS.
Regards Ben