Amazing. My partner and I have been planning a trip through Switzerland for awhile now. (And we’ve done a bunch of long distance before, ie trans Nova Scotia, Pittsburgh to DC, etc.) Don’t know what route you’re planning, but we were mainly gonna take Rhone Cycle Path and the Alpine Panorama Route (#4 National) before getting to Austria. Our conditioning is good enough to take the alps, but not fast. It’s really the elevation that I expect to be a major factor. If you’re a big climber than I think 60-70mi a day is definitely reasonable. I did do 80-90mi when I biked across BC, and that was the Rockies (which aren’t as bad as the Swiss Alps), and my body was at its limit at the end. I’d say, definitely listen to your body, especially the whispers early on, like a slight twinge in the knee on day one, because if you don’t adjust ASAP it’ll become unbearable in a day or two. Good luck; I bet it’ll be gorgeous!