Looking for opinion on my itinerary

You may find that you have enough to see in Nuremberg or Bruges that you don't want to do a day trip or not as many. Nuremberg in particular has a lot to see and it looks as if you won't have much time for it.

For the Munich-Nuremberg train trip it depends how fast you want to get there. The fastest trains are ICE expresses which take just over an hour, but these are expensive if you book on arrival. You can get cheaper tickets in advance, but they may well be limited to a specific train, which you might miss if your flight is delayed. If you are willing to sacrifice time for reduced fare and increased flexibility, you can take an RE train, which is cheaper but slower (from just over 90 minutes to almost three hours depending on which one you take - check before you board). For both of these you will have to get from the airport to the city-centre Hauptbahnhof by local S-Bahn train first. If you intend to take the RE, the best choice is to get a Bayern Ticket at the airport - this is a day pass which will also include the S-Bahn to Munich Hauptbahnhof and any bus/tram/U-Bahn trips you want to take in Nuremberg after you arrive.

And I'm wondering if I already have too much jumping around??

I think that is true.

We'd like to see the Alps if possible.

That's of course possible. Garmisch/Mittenwald and Füssen are not far from Munich.

I have the first 10 nights pretty much figured out with train and
hotel reservations. Although I have not purchased train tickets from
Bruges to Boppard, and my hotel reservation in Boppard is cancellable.
So if there is a better plan, I am open to changing it.

I'm sorting out your words and reading between the lines here... you are only able to change the 2nd eight days, while the first 8 days will remain as they are... is that correct?

If I could have figured it out, I would have loved to make it to
Strasbourg, France, by maybe spending 2 nights in Rhine.

Both Strasbourg and the Alps would not be unmanageable - except that your plan has given over most of days 5-8 to train travel for Bruges/Ghent, which takes you so far across western Europe from your starting point that your time is now probably insufficient for both Strasbourg and the Rhine. On the whole your approach is to stretch your time too thin - (you are doing this with your 3-night stay in Nuremberg too) - and this long journey and prolonged stay in Belgium is one of the main culprits in your itinerary. Geography should guide your choices here... and Bruges is a city too far. (Flying into Brussels and out of Munich would have worked well for a visit to Bruges, but the flights are set, right?) Also, Bruges tends to be very much about museums for most visitors, IME.

Here's how I'd revise your itinerary:

Munich Airport > Nuremberg (5 nights?)/Würzburg/Bamberg/Rothenburg > Boppard (4 nights?)/St. Goar/Bacharach/Mosel town/ Cologne > Strasbourg (2 nights?) > Munich (3 nights?)/Dachau/Alps > Freising (1 night)

Rhine Cruises: Bingen-Rüdesheimer offers the "Loreley Cruise" from Bingen to St. Goar - the most scenic part - through Nov. 3.

" I'm sorting out your words and reading between the lines here... you are only able to change the 2nd eight days, while the first 8
days will remain as they are... is that correct?"

Russ, yes, the first 8 days can not be changed. Bruges is on our list of places to see. Since we were so close, and only a 50 euro train ticket away, we decided to go for it. Ideally we'd have flown into Brussels and out of Munich, but we got a really cheap, and also direct r/t ticket on Scott's Cheap Flights and couldn't pass it up. I agree, that decision definitely impacted the other places we'd like to visit.

Given that, what changes might you suggest for the last 7 days? I haven't purchased my return ticket from Bruges, so I still have some flexibility there. From what I see most of the trains from Bruges connect in Brussels and then go on to Cologne or Frankfurt.

Philip, I agree we probably need to take out one of the day trips from Nuremberg and probably Bruges, too. Its so hard because all of these towns look so interesting and cute! We really enjoy looking at old architecture. If I eliminate a day trip from Nuremberg, which would you visit: Bamberg or Rothenburg? Also, thanks for the train advise.

Any suggestions of tours and what to see and do in Nuremberg? We visited Austria, Hungary and Prague a couple of years ago. We did a tour of a concentration camp and most of our tours talked about Hitler and that time period. It was informative and super sad, but I'm glad we did it. We plan to go to Dachau, but am not sure we want to spend any more time on that this trip. We love to spend our whole day outdoors, although we are interested in seeing a few castles, too.

It's interesting to hear the additional comments you've made about your preferences... sounds like you'd just as soon drop the concentration camp experience and places where old-world architecture does not figure prominently - and instead linger in some old-world spots. And you want to see the Alps.

Back first to Nuremberg and making time to see it... N'berg is a big place that feels much smaller in the old town zone, where the atmosphere is terrific and where you should book. (We enjoyed the Burghotel last year, but there are other good places as well.) There's a lot you can see and enjoy there.

https://tourismus.nuernberg.de/en/nc/discover/walking-tours-round-trips/news/old-town-walking-tours-in-english/
https://tourismus.nuernberg.de/en/discover/places-of-interest/

It actually sounds to me like Rothenburg would be more to your personal liking than Bamberg if you'll be dropping one of those day trips.

"I haven't purchased my return ticket from Bruges, so I still have some flexibility there."

Here's an suggested plan for the Rhine/Mosel.

Day 8: Do your Mosel visit today. Pack a lunch and take the train to Cochem for one night (Lv. Bruges 9:08, ar. Cochem 14:40, fare is €29.90 from DB.) Drop bags at hotel and walk the enchanting old town. (This eliminates the need to backtrack from Boppard on a day trip later.)

Day 9: Train to Boppard (8:44 - 10:14) for 2 nights. Drop bags. See town, have lunch. Get over to the chairlift in the afternoon to enjoy the view from Gedeonseck Terrace (a fairly short walk from the top of the lift.)

Day 10: Train to Bacharach (9:16 - 9:35) for a look around; train to Bingen Rhein Stadt (12:06 - 12:26) for cruise back to St. Goar (13:15 - 15:05.) Visit Rheinfels Castle and return afterward by train to Boppard.

Day 8 is October 22, right? At present you can get a ticket from DB that covers both Day 8 and Day 9 train travel for €29.90 each (I can explain later how to get the schedule above or a similar schedule at this price.)

And then you have the last 5 days. I honestly don't think Würzburg is what you are looking for. Munich isn't either, really. Here's my suggestion:

Day 11: Train from Boppard to Garmisch-Partenkirchen (9:16 - 15:54) for 3 nights, 2+ days surrounded by the German Alps, the outdoors, and some interesting architecture. You might want to get in on the Fraundorfer Inn's Bavarian Evening.

Mittenwald (easy day trip from G-P)
Mittenwald guide
Area train lines

Day 14: train to Munich for a day and a night. See whatever you might have had in mind.

Day 15: train to Freising as planned

Too much travel and a hectic pace. Suggest eliminating some places.

For the Mosel area, check out Trier, Germany

Thanks to each of you for your ideas and expertise! I finalized my itinerary. It took weeks and it wasn't easy. I started out thinking we would "do" Germany once. It is too big and spread out. We will be back to see the rest another time. We're still jumping around, but we're going to see each of the places we want to see! This is the benefit of not being on a tour! So, to recap, we have 15 nights. Fly into Munich and immediately get on a train to our first stop:

Nuremberg - 3 nights - day trips to Rothenburg and or Bamberg
Cologne - 1 night - Sets us up nicely for train to Brugge
Brugge - 3 nights - Day trip to Ghent
Mainz - 2 nights - Rhine cruise with visits to St. Goar, Bacharach. Decided to stay here because of train access.
Wurzburg - 1 night - Decided to stay here to reduce length of train to Innsbruck - plus really wanted to see this pretty town!
Innsbruck - 2 nights - Needed to see the Alps! Easy to get back to Munich: frequent and short train ride back.
Munich - 3 nights - day trips to Neuschwanstein, Dachau.

Fly home happy and exhausted!

A special thanks to Russ! I really appreciate your time and you were spot on with your suggestions!

Next time - OPEN JAW

You are so right! Open jaw definitely would have made this more manageable. I found this super cheap r/t flight so sacrificed that option.