I need to travel from Malpensa Aeropuerto (Terminal 2) to Domodossola (and beyond). I'm aware that there is a direct bus that is faster than the train, but it's only several times per day. Rather than waiting some 3 hours for the bus, I could get to Domodossola faster by taking the bus Autolinea “GALLARATE – MALPENSA – CASTELNOVATE” from Malpensa to Gallarate, according to this timetable. Where and how to I buy tickets and board this bus? I did find a notice that I believe to be about relocating the place to get off the bus from Gallarate to Malpensa Terminal 2, but I can't find information on where to get on the bus and where+how to buy tickets. Do I buy them on the bus, or do I need to pre-book somewhere?
(It's also possible to travel in a roundabout way including local buses and trains: for example, Trenitalia proposes I take a local train from Terminal 1 to Busto Arsizio Nord, then transfer to Busto Arsizio, take another local train to Gallarate. That seems slower and more cumbersome than either other alternative. Travelling via Milano Centrale is an enormous detour of more than 80 km).