>> Alpenrose, you travel a lot on postbuses - do the long distance ones have an on-board toilet? or do you need to rely on scheduled toilet stops?
No, none of the PostBuses have on-board toilets. The longest point-to-point route I have travelled on is the Palm Express, which is about 4 hours. There is a 20-minute break at Chiavenna station at 14:00, just over 2 hours into the trip. That is the only PostBus route I have been on that had a scheduled break.
Travelling from Saas-Fee to Domodossola took about 3 hours on two PostBuses, but when planning the trip with the timetable, I increased the standard transfer time at Brig to allow for a loo break at the Brig railway station.
The Four Passes trip (which I think you have done) took all day, but we had a break of 20-30 minutes at least every hour.
Most other PostBus trips I have done took well under 2 hours and include:
St Moritz (station) to Soglio (village) - 1 hour 40
Flüela Pass (Davos Platz station to Zernez station) - 1 hour 10
Scuol (station) to Samnaun (Post Office) - 1 hour 25
Chur (station) to Bellinzona (station) - 2 hours 20
I also did a round trip Zernez (station) > Val Müstair (monastery) > Mals (station) > Martina (village) > Scuol (station).
My main reason was to visit the Claustra Son Jon in the Val Müstair when I was staying in Scuol, and I decided to go back to Scuol via Italy and Austria :-D to see some different scenery. (It was worth it!). I spent several hours at the monastery and had a refreshment break between buses at Mals/Malles station in Italy's South Tyrol (which, as you might already know, is a German-speaking enclave in Italy).
So that was four bus sectors
Zernez to Müstair - 1 hour 07
Müstair to Mals - 25 minutes
Mals to Scuol with a short transfer in Martina - 1 hour 28
This route is described here:
I hope to write about my visits to Claustra Son Jon and Samnaun at some stage!