I would say you’re doing a lot in that time, but it’s your choice how fast to go.
Day 1 Travel to X, Day 2 Travel to Y = you don’t get to spend much time in X!
The Rhine Valley is the wrong direction if you want to go to Berlin. It makes it a long day. I thought it was pretty, but not sure I’d go out of my way to see it. You could also consider the sleeper from Brussels to Berlin if you don’t go to Cologne.
Berlin (& Leipzig) and the Czech Republic - I could spend a lot of time there! I really enjoyed Brno. Often, I think the smaller cities (Leipzig, Brno, Bratislava, Bern, Utrecht) are much more enjoyable on an express itinerary like this than Berlin, Prague, Vienna, Amsterdam. You get more flavour, less expense, less time spent moving around a big city. Obviously you'll miss out on the big ‘sights’ if that’s important.
Switzerland - excellent trains! If you’re short of time, I’m not sure I’d do both the Glacier Express & the Goldenpass. They’re gorgeous, but take a bit of time to position yourself from the rest of your itinerary. I’d pick one and use the time to stop off somewhere along it.
Nightjet is a great way back up towards Brussels from Switzerland. You cover a lot of ground quickly. Get a couchette or sleeper reserved as soon as you can - they sell out.
I'm assuming you'll agree the '10 travel days in 2 months' is the best Interrail Pass option..?
That might leave you a bit short, depending on how the days pan out, but then so might the next one up, 15 days continuous.
I agree that it’s probably the best one. Any shorter trips you can pay cash for if it looks like you’re going to use up all your days.
Some advice from me too :)
If money isn't an issue I'd definitely get a 1st class pass. The price difference isn't huge and at this time of year most European trains are crowded. It would make a better experience overall in my opinion !
Optional reservations are also free in Germany, Austria, Czechia when booked through the Austrian railway company ÖBB. Make them at any time, just for peace of mind.
About the Switzerland part : you could easily arrive in Buchs via the direct RJX from Vienna and then change for Chur where you'd spend a night. Or take the Vienna - Zurich night train and stop in Buchs early in the morning before starting your day.
After Chur you follow the Glacier Express route according to your plans, at least as far as Brig for Montreux. Also possible to do the full route from St. Moritz but obviously it takes more time so maybe spend the night somewhere in the Engadin Valley.
Feel free to ask further questions. Some reservations will need to be booked well in advance (Eurostar, night trains) but other than that full flexibility in that part of Europe !
Thank you very much. Some great points there. Really appreciate you taking the time and effort to reply!
I'm assuming you'll agree the '10 travel days in 2 months' is the best Interrail Pass option..?
That might leave you a bit short, depending on how the days pan out, but then so might the next one up, 15 days continuous.
I agree that it’s probably the best one. Any shorter trips you can pay cash for if it looks like you’re going to use up all your days.
Many thanks for your replies - really helpful, and I'm very appreciative!