<<"Lucerne is 1 hour from Zurich.">>
Trains at xx47 go direct, with a stop in Zürich.
Trains at xx18 require a change at Zürich main station.
<<"Depends what time you arrive but if you lob into Geneva the the most scenic way to get to Wengen is via Montreux and Zweisimmen on the Golden Pass Line (www.myswissalps.com/go ldenpass). A much longer train ride. ">>
Between 5 1/2 and 6 houers.
Scenic trains are often slow. That route requires a few changes.
<"You won't have any problem finding stuff to do for 3 nights in and around Lucerne and Wengen. See the "What to Do" tabs on my earlier links.">
Do you like to walk, hike, or trek?
<<"Another alternative if you arrive at Geneva is to slipover to Zermatt and check out the Matterhorn. Have a night there and continue on to Wengen. Make sure you go to Wengen via Kandersteg. ou will then travel on the Regio-Express Lötschberger train over the traditional, more than 100 year old mountain route, giving you a wonderful view along the impressive peaks and down into the Rhone Valley.">> Agree. It does add a 3rd overnight location, but it is a reasonable idea.
We have stayed in Luzern and at nice villages around the lake for as much as 1 week at a time and not exhausted all the possibilities. If you want to hike, you can spend a few weeks with no trouble.
The Jungfrau region gets short shrift at only three days, unless they happen to be cloudy ones. Then, day trips to Bern, for example, become appealing.
On ocasipn, when the weather in the Jungfau regipn is clouds and fog from top to bottom ( it comes in layers, by the way) we have doe this hike:
It goes along part of the "Lötschberger " route that Rockoyster mentioned.