Swiss saver and swiss saver flexi

Hi Msaadm,

I am new to this forum and its my first trip to Switzerland. Can you kindly advise me on the passes (flexi and non-flexi) I need to purchase for 2 person? Or are there better alternatives as we plan to move around on our own since we are spending a few days in each city. My plan is :

Day 1 Milan to St Moritz (Bernina Express)
Day 2 St Moritz
Day 3 St Moritz/ Zermatt (Glacier Express)
Day 4 Zermatt
Day 5 Zermatt/Interlakan
Day 6 Interlakan / Bern
Day 7 Bern (1/2 day)

Thank you

Tangosin

Dear Annika, thank you for your reply. I have a few more questions, kindly help :

1) Does it mean for day 2,4 & 6 , I will get discount for tickets that I buy?
2) Now I plan to take the Bernina Express all the way from Milan, Tirano to Chur, spend a night in Chur and then to St Moritz the next day. Is there a train from Chur to St Moritz ? Do I need to book ?
Likewise for Zermatt to Interlakan and Interlakan to Bern, do I need to book the train rides before I leave for vacation.
3) Once I purchased the Swiss Saver Flexi Pass, where do I log into to purchase the Bernina and Glacier Express and do I have to pay extra?
4) Do you suggest I stay over night in Interlakan or is Grindelwald a nicer place to spend a night ?

Thanks !!

Tangosin