Help with itinerary 30 days (Belgium, Netherlands , Germany)

https://www.ricksteves.com/europe/germany/mosel-valley
https://www.ricksteves.com/europe/germany/cologne
https://www.ricksteves.com/europe/germany/rhine-valley
Also look into these deserving places which Rick Steves mostly ignores:

Aachen
Mainz

You might want to search through this forum to see what other travelers have done and come up with a draft itinerary. Or maybe look through some guidebooks as well and pinpoint cities and areas that appeal to you. Once you have a proposed itinerary, come back and we can help you fine tune it.

Once you have the cities in mind, it's easier to figure out the smaller towns and areas. Another thought is to look at the itineraries for the Rick Steves tours for those countries and pull from them, but then tailor it to your schedule. He published all the itineraries online. For example, here is the Germany itinerary for the 13 day Best of Germany tour - https://www.ricksteves.com/tours/germany/best-germany-tour

And here is the Netherlands/Belgium itinerary: https://www.ricksteves.com/tours/holland-belgium/belgium-holland

Now, having said that, I will tell you that I spent 30 days in Germany last year. I started in Berlin, then went to Nuremberg (with day trips to several nearby cities), Gengenbach (in the Black Forest), the Rhine Valley (Boppard), and then Cologne, Aachen and Hamburg. I was also in North-Rhine/Westphalia but that was for family research.

5 years ago, I went to the Netherlands and Belgium. I stayed in Amsterdam mostly but did day trips to places like Hoorn, Den Haag, Leiden and Haarlem, then spent 3 days in Belgium, staying in Ghent and visiting Bruges. I loved Ghent and Bruges was pretty cool, too. In fact, I loved every place I went to, although I was not as enamored of Haarlem as others here are. Leiden was beautiful and a very walkable city, with charming streets and canals and some nice museums. Hoorn was also pretty neat - it has a fishing village type atmosphere and I loved my day trip there. Leiden and Hoorn were probably my favorite place outside of Amsterdam, which I also loved. I really want to go back there as there are many other places I would love to visit.

With regards to Germany, I skipped Bavaria for the most part because I had been there before, so you would undoubtedly want to include that. I loved Gengenbach in the Black Forest and would definitely go back there again. The Rhine area was also lovely and well worth a stay. I also loved Cologne for its magnificent cathedral and enjoyed Aachen as well, which has some incredible history there.

Lots of choices. Almost all of them good. For Belgium, go to Brugge. If interested in WWII, then perhaps Bastogne. Along the Rhine there are many villages and castles to be seen and visited. In the small town of Oberwesei there is a town wall you can walk and one of my favorite churches, the Liebfrauenkirche. In Mainz there is the Guttenberg Museum and St. Stephan’s Church with the wonderful Chagall stained glass windows.

On the way to Amsterdam stop or stay in Cologne and visit the cathedral. Pay the extra to see the treasury.

Some recommend staying outside Amsterdam in Haarlem for cheaper lodging. It’s a short train ride away.

There are many great sights all over Belgium! If you would feel comfortable sharing the general area where you will be visiting your friends, I and others on the Forum could perhaps provide some suggestions more targeted to that area.
Sounds like a great trip!

Thank you all for your suggestions..
I still need help figuring out a pass or buying tickets the day of the trip.

Total days :30
Itinerary: in and out of Amsterdam.
6 days in Haarlem going to Belgium for 6 to 8 days.
Thinking about going Brussels to Paris and then Tour. (4 days)
And also wanting to go Germany ( Cologne-Munich)

I am confused about how many days in each city and what other cities.
What should I use for figuring out trains and routes.
Any help is greatly appreciated.