Hello Travellover62
Yes, you can purchase route-based class upgrades, which are available as
- Supersaver class upgrades (when available, you must use the SBB Mobile app for this), or
- point-to-point class upgrades.
Unlike tickets, which must be purchased before boarding a public transport service, point-to-point class upgrades you can purchase with the conductor, provided you travel on an IR or IC train. I suggest doing so since you are not familiar with the Swiss rail system. The minimum fare on the IR/IC trains is CHF 10 per ride, for the routes you mentioned above, you will simply purchase the upgrade cost due as it will coste more than CHF 10. Or, go an see a travel agent at the station’s travel centre. The agents can sell you the right upgrade tickets.
Class upgrades are available at full or half fare. The latter is available if you hold the Swiss Half Fare Card in addition. This information you did not provide.
https://sbb-tickets.cc/en/tickets-offers/tickets/point-to-point-tickets-switzerland/class-upgrades-supersaver-class-upgrades.html
Also, it is my understanding that even though our travel company gave us times for the tickets we can use the tickets at anytime on that particular day.
Yes, it allows travel at will on all major trainlines, buses, trams, boats, etc. It has limited validity for moutain excursions, though.
Please let us know if you have got more questions.
Kind regards,
Roland