How much would i be able to do in Europe for 3 weeks?

When in Zurich, try to get to Stoos. It is a skiing village that is only accessed by a cable train. Personally , I love it.Also, even though you are not into history, it may be worth your while to stop into a a WWII prison camp where the folks were exterminated. It is truly a moving experience! Enjoy your trip and have a wonderful day!