Two strategies that may be a toss up. Assuming 2 adults over 25 yo.
1. Buy a 15-day Swiss Travel Pass for 429 CHF per adult.
2. Buy a Half Fare Card for 120 CHF per adult plus a 6-day Berner Oberland Pass for 220 CHF (with the HFC discount)
Advantage of #1 is easy and gives full coverage for all transportation to your lodging locations, plus certain journeys in Luzern like lake boats and mountain rides like to Rigi and Stanzerhorn. Disadvantage is reduced coverage for certain mountain rides in the Berner Oberland, especially going to the Jungfrauoch. It only gives a 25% discount above Wengen.
Advantage of #2 is better coverage in the Berner Oberland, fully covering above Wengen to Eigergletcher and 50% with the HFC to Jungfraujoch. Disadvantage is you will have to buy some journeys with the HFC, like Zurich airport to Luzern (15 CHF), Brig to Zermatt (19 CHF), Zermatt to Bern (45 CHF), Bern to Zurich airport (28 CH), and any excursions in Luzern. You will also have to take a slower route from Spiez to Brig on the way to Zermatt since only this route is covered by the BOP. But it is a lot more scenic.
I'd go with #2 if you definitely want to go to the Jungfraujoch, otherwise #1. #2 saves 78 CHF per person on the Jungfraujoch.
PS. You could spend a day cruising Lake Luzern and doing Rigi and Stanzerhorn by buying a Saver Day Pass with the HFC for 44 CHF per person. You have to buy this 60 days before your date of use to get the 44 CHF price, as the price goes up as you get closer to your use date.
