I have 4 nights on my own between organized itineraries. One ends in Venice and the other starts in Berlin. Since it's during Oktoberfest time, my thought was to fly to Munich and spend at least 2 nights there so that I could go to the Okberfest. (It's nostalgia for me, since I lived in Germany a long time ago.) I could spend 2 more nights in Munich and then take the train to Berlin. Or I could take the train from Munich to Nuremberg, spend 2 nights there, and then take the train to Berlin. I have been to Nuremberg many years ago. Again, it's nostalgia for me to go back. I haven't been either place in quite awhile, though. So I was wondering if anyone has any tips or opinions. Thanks.
If you don't already have lodging of Octoberfest in Munich you need to start looking. It will be expensive. I like both towns, visit at least once a year, but would suggest you consider someplace more in line with Venice-Berlin. Like Prague, or Vienna. Or, even better, would be to fly to Poland. Ryanair will get you into Wroclaw from Venice for less than $50 and a really good hotel will run about $100/night.
Nothing against nostalgia but how about Prague and / or Dresden on the way?
I'll be in Prague and Dresdan after Berlin. However, I have wanted to go to Poland and haven't had the chance. That's something to look into for sure.
(Yes, the hotels around Munich are very expensive around Oktoberfest. That's one reason I'd only stay 2 nights.)
Life is short. It's cool when you can find pleasure and beauty. If you have grand memories of Munich and Nuremberg and it adds to the beauty of your life, re-visit those places -- don't be distracted by places thrown out by people who know absolutely nothing about you. Trust your instincts. I think 2 nights in Munich and 2 nights in Nuremberg are fine. I like to minimize moves (and I have no particular attachment to Munich or Nuremberg), so I might be inclined to do Nuremberg as a day trip to minimize a move, but I also understand the cost issue. Four nights in Nuremberg with a day trip to Munich/Oktoberfest might work, too, and be cheaper?
On your way to Berlin, consider a stop at Erfurt if you haven't been there. There is a large locker area at the train station to store bags if you want to walk around and check out the place. It is a quite attractive city with a large half-timbered old town that largely escaped Allied bombs during WWII. It has an Oktoberfest of its own -- far smaller than Munich's -- that I found quite enjoyable. https://www.erfurt-tourismus.de/veranstaltungen/hoehepunkte/erfurter-oktoberfest (the main Oktoberfest website is linked on that page but right now covers the upcoming Spring Fest).