Itinerary help

If you choose Frankfurt as one of your bases, it is easy to visit these towns by train, all within an hour of Frankfurt:
Limburg, Marburg, Mainz, Wiesbaden, Eltville, Büdingen, Gelnhausen, Idstein, Bad Homburg, Kronberg, Seligenstadt.

These events are happening during that time period.

Worms Medieval Fest – 19-25.05
Königstein Jousting Tournament – 20-21.05
Frankfurt City Forest Fest – Wäldchestag – 26-30.05
Medieval Jousting Tournament at Ronneburg Castle – 27-29.05 (not easy to get to with public transportation)
Ober-Wesel Medieval Fest – 27-29.05 (more than an hour away, but you could combine this with a cruise on the Rhein, starting in Rüdesheim, and then train back to Frankfurt)
Mainz Night of the Museums – 3.06
Rüdesheim Magic Bike Rally – 8-11.06
Frankfurt Alte Oper Plaza Fest – 21-30 June

Thank you so much! I hadn’t thought of using Frankfurt as one of our bases -so many great suggestions

Choosing Munich as a hub of course is a good idea to explore southern Bavaria - need to say that becasue I'm living in Munich :-)

But I would really like to bring Hamburg on your map. Germany's second largest city is full of history, culture and it is modern at the same time. A very maritime city in northern Germany with a special vibe. Like all the big cities in Germany with perfect public transport Hamburg is easy to navigate.
Would be great fun to visit cities like Lübeck (queen of the German Hanseatic League cities) as a day trip. So many more places one could day trip from Hamburg :-) You could even visit Germany's only offshore island Heligoland.

I'd opt for 5 bases over 6 so that you can maximize or minimize time in this base or that base more easily.

One thing to keep in mind about Germany is that large cities generally abound with post-war construction. To visit places that somewhat resemble the Germany of previous centuries, you would do well to allot time for outings to smaller, old-world places outside your base towns. Take heavily bombed and handsomely rebuilt Nuremberg for example (a great choice for its many museums and many other reasons, btw.) From there, the UNESCO World Heritage old-town of Bamberg is only 45 train minutes away. Also quite close is the excellent collection of historic buildings at the Franconian Open-Air Museum in Bad Wimpfen. (I suspect that Jo is offering you the same kind of advice when she mentions places like Idstein, Seligenstadt, and Büdingen. Unfortunately, you can't rely only on Rick Steves' materials alone to inform yourselves on most options like this, so do some googling.)

One reason I like Nuremberg so much is that it's mostly walkable. That's not the case with Berlin, and not with Munich or Dresden either, IMHE... you're pretty much tied to the underground, trams, buses, etc. if you don't want to wear yourself off at the ankles. Other base-town options where walkers can be a bit more independent:

• Look into Hamburg if you haven't. This is a much-neglected and distinct part of the country, and outings from Hamburg to Lüneburg and to Bremen offer something quite different.

• Give Mainz and its museums a thought as well. Mainz also has some outstanding cathedrals and its own small "old-town" zone on/near Augstinerstrasse (the Kirschgarten is an adorable spot.) Some of the events/destinations Jo brings up are just as easily - or more easily - reached from Mainz (Oberwesel, Worms, Rüdesheim, and of course Mainz itself) and you can day trip from Mainz to Frankfurt as well. And Mainz itself is quite walkable with dozens of streets around the town center completely given over to pedestrians... they're all marked in pink on this map.

I would definitely add the north. It doesn't fit people's expectations of Germany, which is all the more reason to add it. Germany is not known as a maritime nation, but Hamburg is all about water. It's not a city with a central old town, but it is a fascinating place with a vibe of its own. It has always been a bit different from other German cities.

The north boasts the Wadden Sea, gorgeous landscapes, and great sites and festivals. Great places like the Lüneburg Heath and Lüneburg itself, St. Peter-Ording, Lübeck, Glückstadt (major festival June 8-11), Bremen, and of course Hamburg itself are worth seeing if possible.