Hi Barry
We did this (although not a tour) in Easter 2005. We took the Dover-Calais crossing, then drove the 600 miles in one go (less comfort breaks and driver switching, my wife and I sharing 2-3 hour shifts behind the wheel) to Lauterbrunnen near Interlacken.
We disembarked in Calais at about 10.30am, and arrived in Camping Jungfrau at about 11.30pm - if only our roads were so traffic (& snow!) free.
We did drive to Italy one day, across and through the Alps ending up at Lake Maggiore. This was solo in the car. There are some very, very long ascents and descents in the mountains. Your car's power will diminish at higher altitudes (some roads were over 6,000 metres above sea level) and we had to take a train through one mountain range - a bit like a basic Eurotunnel.
So, I'd recommend you check your car's towing ability at high altitudes and that you have plenty of power in reserve - or choose a longer more level route!
Be aware of your Sat Nav, if you use one. On the way back, ours directed us up a very narrow mountain lane, in the pitch dark. We were suddenly confronted by a 30' wall of snow across the road. Nothing for it, but to do a many point turn and retrace our steps. A bit disconcerting when there are no crash barriers on a single track mountain side road and all your headlights show is the valley floor several thousand feet below!
Thank goodness we were driving solo, had the van been on the back we would have been completely snookered.
Have a great time, Switz is a beautiful country and so clean.
Mike