This all rather depends on what your actual plans are. Are you doing a two-centre trip spending time in Zermatt, then in Luzern? If so I would treat the transfer day** as just that, then do the lake activities around Luzern as separate excursions once you are in the area. I think it would be more relaxing for you that way.
** I posted the text below for another forum visitor thread on here, so you need to reverse the steps:
I would advise you to limit your journey Luzern - Zermatt to the 'regular' route. You will see more than enough scenery going that way and it is not always a great idea to go 'round the houses' on a 'link' day.
Take a Luzern - Interlaken express hourly train from Luzern
Route: Brünig railway line
Views: various lakes, steep incline sections, fields, forest etc
Change at Interlaken Ost into any train Interlaken - Spiez
Route: BLS railway Interlaken branch
Views: Thunersee (Lake Thun). Sit on the right hand side of the train on leaving Interlaken
Take the BLS Lötschberger unit train Spiez - Kandersteg - Brig
Route: Lötschberg mountain route
Views: spirals and loops at Blausee-Mitholz on the 'north ramp' between Frutigen and Kandersteg; famous view of Rhone valley on descent from Goppenstein to Brig (sit on the right hand side of the train to get this view)
At Brig, make your way out of the front of the station to the station forecourt. The Zermatt railway line platforms are situated in the street. Take the hourly Brig - Zermatt regional train
Route: Brig - Visp - Zermatt railway operated by MGB (Matterhorn Gotthard Bahn)
Views: Mattervispa river valley, river rapids, hillsides, valley, chalet gardens backing on to railway, smallholdings with goats and other animals, rack sections