We will be traveling (driving) from Konstanz Germany to Staufen Germany. On the way we would like to visit the Rhine Falls. Is there any way to drive to the falls in Switzerland and avoid paying the Swiss highway tax? We will only be in Switzerland for a few hours!
The toll sticker is only for motorway driving (and some "Schnellstrassen". All other roads are free and do not require a sticker. see the official information here: http://www.ezv.admin.ch/zollinfo_privat/informationen/00421/index.html?lang=en
I haven't driven into Switzerland in 3 years, but at that time, if you entered the country from a manned checkpoint, you had to buy the sticker before you could drive any further. Switzerland recently entered the Schengen zone, so I'm not sure if they have any border checkpoints remaining. But if you get stopped by a police officer and don't have the sticker, that probably wouldn't be good...
As Tom has indicated, the tax takes the form of a "vignette" which must be visible on your windshield. It costs approx. US$40 but if a cop sees you do not have it, the fine is SwFr 100, just under US$100. Consider it an entry fee to the site you want to visit.
In your particular case, it means that you should avoid the Swiss A4 expressway south of exit Schweizerbildsstrasse, since the A4 (except the small stretch from Bargen/Neuhaus am Randen to Schweizerbildsstrasse) requires a toll sticker, thus north-south tunnel tunnel link through Schaffhausen requires the sticker.