Amsterdam to Switzerland to Cinque Terre

Day
01. Fly Amsterdam to Geneva. Train to Lausanne - 2 nights
02. Day on Lake Geneva / Montreux
03. Train to Interlaken and on to Lauterbrunnen - 3 nights
Stop in Bern for a few hours on the way.
04. In the mountains - Murren
05. In the mountains - Wengen / Grindelwald
06. Train to Luzern - 2 nights
07. Day to Pilatus
08. Train via Milan to Cinque Terre

My suggestion is slightly different. In that situation, I'd probably arrange things something like this.....

• fly Amsterdam to Zürich (easyJet has flights every other day for as low as €39.99 but you'd have to plan your Itinerary accordingly).
• train from Zürich to the Berner Oberland / Lauterbrunnen Valley (4 nights?) Explore towns in area, hiking and day trips. If you're planning to visit the Schilthorn or Jungfraujoch, you'll need to increase the budget as they're not cheap!
• train from Berner Oberland to Lucerne (3 nights?) See Lucerne and day trips to Pilatus, Rigi or wherever for incredible mountain views. The Museum of Transport in Lucerne is fantastic!
• Train to the Cinque Terre. Which of the five towns are you planning to stay in?

Thanks so much for your advice, it's much appreciated.
Would you recommend breaking the journey up between Lucerne & Cinque Terre with a night somewhere en-route?

We are thinking of staying in Monterosso during our Cinque Terre stay. Would you recommend?

Thanks again

Yes, Monterosso is absolutely a good choice (it's my favourite, so I'm somewhat biased). It's the largest town and therefore has the greatest number of hotels, restaurants and other tourist amenities, as well as the best beaches. However, it's getting a bit late to get a booking for June, as many places will already be fully booked. See what you can find, and if you need other suggestions, post another note here.

Regarding "breaking up the journey" between Lucerne and the Cinque Terre, my preference would be to crack on and make the trip in one day. While that's a bit of a longer trip (~8 hours), my preference would be to spend the time enjoying Monterosso and the Cinque Terre, rather than wasting a night somewhere else. There's a train departing Lucerne at 09:18, arriving Monterosso at 17:05 (time 7H:47M, 2 changes), which is probably the one I'd use. That's a good time to arrive as you can check-in to your hotel and then go out for a fine meal in one of the restaurants, perhaps one with a patio overlooking the ocean.