Flying into Zurich and taking a train to Luzern. Stay there for 3 nights. Wanting to do a day trip to Murren. IS THE WEATHER NICE ENOUGH IN THOSE AREAS AT THE END OF MARCH OR SHOULD WE RECONSIDER?
The end of March may or may not be still the ski season, depending on the conditions. And if it isn't... it will be the shoulder season, when almost everything closes.
Mürren might be nice, but it's not a destination in and of itself. It's a place to base yourself for mountain excursions. So if you're there to ski, great. If you're there to hike... wrong time of the year.
Luzern should have enough to keep you busy for 3 nights. As mentioned above, Mürren is not day trip material.
justin,
If you want to take a day trip to Mürren just to have a look at the place, I'd suggest checking the weather first. If it's going to be a sunny and warm day, a day trip should certainly be possible. Maintenance on the Schilthornbahn isn't scheduled until 18 April, so you should be able to take a trip to the Schilthorn also (it's expensive though).
It's likely to still be winter in that area at the end of March. Have a look at this webcam to get info on the current weather there. Today it's snowy.