Amsterdam, Brussels, Germany, Austria, Switzerland,

I'd have a waterproof rain layer especially for your earlier travel and perhaps a puffy vest or jacket that will fit underneath, depending on how cold-tolerant you are.

I think everything you've listed can be done by train although I am not sure about Fuessen to Reutte.

I do have some comments about how you've divided your nights:

I'd go with 3 nights in Trier and 2 in Baden-Baden (or one unless you are a total spa fan). I found a lot to see in Trier - very nice museum, Roman Ruins, a couple of big churches if any of those things are of interest to you. On the other hand, I'm not a spa person and the 1 night I spent in Baden Baden on a Rick Steves tour was more than enough. Did you have specific plans for this area to give it 3 nights?

On another tour, I stayed 2 nights in Reutte and perhaps we didn't see the important bits but what I did see I'd not make a day trip to visit. On that tour is was used as a base to visit Neuschwanstein. Did you have something special in mind?

I'd also want 3 nights in Lauterbrunnen although it may be too early to do any mountain hiking. What was your plan here?

You've got a huge number of moves which would be tiring to me. Hope you are traveling light!

I would take one night from Brussels and one night from Bruges and add both to Amsterdam. Brussels is a large modern city and can easily be seen in one day. I was unimpressed with Bruges (it's nice for one day but very crowded) and was very glad that I stayed in Ghent (another good option). But I loved Amsterdam - there is so much to see in the city, and there are multiple and wonderful day trips available to places like Hoorn, Delft and Leiden.

I also second Pam's recommendation to spend less time in Baden-Baden (unless you are using it as a base for the Black Forest area).

Great itinerary. I’m jealous that you’re able to take the time.

Brussels- if you’re a car buff, AutoWorld is the most amazing car museum on earth. We stayed at the perfectly located and super comfortable Hilton Grand Place.

Bruges - stayed above the Cafe Red Rose. I loved the convenience to the amazing beer bar, but our room was ridiculously tiny. YMMV. We had fun at the chocolate museum, did the tower climb and loved the little boat ride. 2 nights is plenty but a third to soak up atmosphere isn’t a horrible thing.

Amsterdam - I felt rushed w 3 nights. A lot of stuff to see. Anne Frank annex advice - choose a later time. Less crowded. Expect to walk a LOT. Cafe Golem is a great little place for a beer.

Munich - 3 nights is good, more is good too if u want to chill. We just made a res for Motel One Sendlinger Tor for our return trip. Dachau is very worthwhile and convenient but it’s heavy lifting. It will cast a pall on your day (and that’s okay).

Zermatt - is beautiful. We REALLY recommend the William Tell Express /Gotthard Panorama Express train into Italy. We stopped for lunch in Bellinzona and I would have loved to explore that town more.

Backpacking for sure this time, still hard getting use to. Baden-Baden was for the black forest unless another town is recommended. I think we may omit Fussen/Ruette, castle are under maintenance with scaffolding. Ghent was going to be a day trip for sure. We're actually staying in Murren, basically atmosphere mountain peaks Jungfraujoch. Can't wait to try the brewed Belgium and German beers. We will be adding more days in Amsterdam since we return home from their. Thanks for the suggestions and looking forward to more. Has anyone attended the old opera house in Milan, was it worth it.

I saw Teatro alla Scala in Milan decades ago and I think it is worth seeing - and would be even better to see a performance there if you have the opportunity (and enjoy opera). :)

That being said, it is definitely worth going to Milan to see the Last Supper. I am not religious by any means but the painting moved me beyond words.

Look at Gengenbach instead of Baden-Baden.
Put the stops in google or another program to get an idea of the time spent with in a car or on the train