As part of a longer trip, my wife and I would like to spend 2-3 days in Switzerland this December. We are both in our 70's, but still fairly active.
Just so we can give you some ideas that will work timewise, , where will you be before entering Switzerland and what country’s next?
You could spend time in Basel for the Xmas Markets for 1 full day. Then go to Lucerne - it's one of my favorites in all of Europe.
Lucerne is very charming and you could go up to Mt Rigi, if the weather is clear. I loved being in the fresh powdery snow, but then again, I'm from So Cal!
The Xmas markets in Bern were the better Swiss markets, IMHO . If I was in Basel, where the two markets are smaller, I'd take a quick train ride to the magical markets in Strasbourg.
Enjoy!