8889 posts
Hello Mpossi and Welcome to MySwissAlps,
“Does it make more sense to go from Interlaken to Tirano so we can take the Bernina Express and then go back to Zermatt to take Glacier Express to Chur?”
Not really. Interlaken to Zermatt is under 3 hours. What you propose might take 3 days!
You might want to look at the map you can download at http://www.myswissalps.com/swisstravelpass/validity and then use the SBB Mobile app (bit.ly/2ICIUHi) to check timetables for travel times.
If you start in Milan you could go to Tirano (direct or via Lugano) to Chur to Zermatt to Interlaken to Austria. That’s just one permutation. You could arrive in Zurich and be in Lugano within a few hours.
See http://www.myswissalps.com/traintickets/italy and http://www.myswissalps.com/traintickets/austria.
Based on your personal itinerary you should read “How to choose the best travel pass” (http://www.myswissalps.com/train/ticketspasses/practical/chooserailpass), download the handy spreadsheet calculator and do the math. The spreadsheet also includes links to the “Where it’s valid” page for all available passes. Be sure to check those pages for each pass you are considering. Study the map AND read all the text on those pages to fully understand what is covered by the respective pass.
How long are you planning to spend in Switzerland? That will dictate what is a realistic itinerary.