Wilhelm Tell route

The quickest route from Lugano to Luzern is via the Gotthard route, and the views are on the climb up to and descent from the tunnel.
If you search for trains on www.sbb.ch it will find the quickest option, 99% the Gotthard route.
You can see the route on this map: www.sbb.ch/content/sbb/de/desktop/abos-billette/billette-schweiz/tageskarten/_jcr_content/relatedPar/relateddownloadlist/downloadList/_bersichtskarte.spooler.download.pdf
Lugano - Bellinzona - Airolo - Gotthard tunnel - Göschenen - Flüelen (where the William Tell Express changes for the boat) - Arth-Goldau (you may have to change here) - Luzern.
Note all the spiral and zig-zag sections on the map, the train really does 360° turns to gain / loose height!

Thank you Chris. Cannot wait to see the mountains in Switzerland- we are coming from flat Orlando Florida!

The good news is, you'll see mountains almost everywhere you look in Switzerland! There is no shortage.

Switzerland is as mountainous as Orlando is flat. I think the lowest point in Switzerland would appear as Mount Everest to a Floridian :-)

BTW, note that the WIlliam Tell requires a First Class ticket. I am assuming - correct me if I am wrong, Chris - that other options include a second class option (and that one could just hop on with a Swiss Travel Pass).

Hope this helps!

Porcupyn

Yes, all normal trains in Switzerland have second class, and all but the most local of services have first class.
If you have a valid Swiss Pass (of which there are many types), you can just get on any train which takes your fancy, and sit in any seat of the correct class (no reservations needed).
All train routes and all stations in Switzerland have at least 1 train per hour, often more, and they all connect. So it is very much a "turn up and go* service.
The William Tell Express is a special excursion train for tourists, and special rules apply.

P.S. Jillian, The lake south of Luzern, used for the boat part of the William Tell Express is called Vierwaldstättersee (though most English-Language guidebooks call it "Lake Lucerne"), it is 433 m (1,421 ft) above sea level, and that is at the bottom of the Alps. The Gotthard tunnel, the highest point of the railway, is 1142 m (3770 ft).

Thank you everyone for your replies. Yes, will be buying my Swiss travel pass. I am definitely more if a "show up and hop on" person rather than reservations so this should be perfect!