Li_mom-

Yes...unless you want to hike all the way up, you can NOT go to Pilatus Kulm (peak) in March since the cogwheel and gondola are closed. Here is the transport link: http://www.pilatus.ch/en/open-facilities/

There's a big transportation museum in Lucerne which your children would enjoy, particularly if the weather is awful. It's right on the lake so you can take a ferry there.
We've always taken the train from Zurich airport to Lucerne - very easy to do. There's a tourist office in the station plus shops and places to get something to eat and drink.