4 nights in Murren then west to Montreux or east to Lake Como/Lugano?

Coming from Zurich, Lucerne would be a good option as it is located in a very picturesque location and there is good transportation from Zurich. As for the Lake Como, that wouldn't be difficult. The fastest way would be to take a train direct to Milan via Lugano, then switch trains to Varenna. Check on the Deutsche Bahn for train schedule. For the train from Milan to Varenna, check on Trenord. I hope this helps some.

I think you can't go wrong, but with just 8 days, I'd stay within Switzerland. Luzern would be my choice for starting in a leisurely atmosphere. En-route to Montreux, you can enjoy the Golden Pass scenic train line via Zweissimmen, which takes 3 - 4 hours from Interlaken. En-route to Varenna on the east side of Lake Como, you could take the Bernina Express scenic route via Chur and Tirano, and connect there to the Italian train, but that takes longer (8 hours Interlaken-Tirano and 1.5 hours Tirano-Varenna).

Why not go to Montreux and fly home from Geneva? No backtracking that way. Get both the German & French sides of Switzerland.

Thanks to all of you for your ideas. The suggestion to fly into or out of Geneva is an easy option for us. I am thinking we should stay in Switzerland and make Italy another trip. We are "seniors" and have decided to not rent a car. We are downsizing our luggage and thought the trains would be an interesting experience. Saying that, we have already visited Zurich and Lucerne so we prefer something new. After our 4 nights in Murren, what is your suggestion about three more nights? By this time I am wondering if we need a scenic train ride. Our preference would be small towns. Do you have some ideas in the Geneva area?