Hello ATC
If you really want to visit Jungfraujoch, you should purchase the Swiss Half Fare Card, with the complimentary Swiss Family Card.
The big question mark: the Jungfraujoch trip. It is costly, the most expensive mountain trip one can do in Switzerland. Not even all Swiss can afford going there. The weather in Switzerland is not predictable more than 2 days out. It is well possible you will end up in a white-out. Would you still want to go knowing the weather is bad, and you will end up in the clouds? My dear colleague @RedBaron once said to a fellow traveller, it would be the most expensive fog you have experienced - very true!
The Saver Day Pass is not valid to the Jungfraujoch, it is as far as Grindelwald, or Wengen.
Also, in my opinion, you are wasting your time with travelling forth and back. Zurich - Grindelwald - Zurich - Geneva. Why not going forward from Zurich, staying somewhere in the Jungfrauarea, and then Geneva. With so little time, it would mean a pity if you spend it on trains, unless you are a train-fanatic.
What do you think?
Kind regards,
Roland