Should we buy our SRP online or buy at the Zurich AP? Our itinerary is not flexible and we want to book reservations on the scenic trains. We have read that booking scenic trains online is not refundable and/or changeable but we are unsure about the SRP.
You can buy at Zurich Airport when you arrive. You do not need a pass in hand to buy seat reservations, so you can do that now if you know your schedule.
Buy it at the airport. It comes like a boarding pass in a protective plastic cover and a map outlining all the routes where you can use it.
Monica, Are you looking for a consecutive day pass, or the flexi version?
For the consecutive day pass, you can buy it at any main rail station, including Zürich Flughafen (airport) station; or buy it online as a "Self print" ticket here: https://www.sbb.ch/en/leisure-holidays/travel-in-switzerland/international-guests/swiss-travel-pass.html
Either way it is the same price. You choose your dates when you buy it, and you cannot get a refund or change your dates after you have bought it.
The flexi pass is not available "self-print", you either buy it at a main Swiss station, or some resellers will post it to you, but that may cost more.
For prices see the link above.