If you're driving in Austria, you have to pay some sort of driving tax that they don't advertise on the roads but you can get it from any gas station in Austria.  If you don't buy the tax, you can get fined up to 500E.  So morale of the story is, when you drive into Austria, stop and pay the tax at any gas station!
Our hotel guy in Munich told us about this!

OK and if you like mountains, I would go to the Eagle's Nest before I went to Neusweinstein (I can't spell it to save my life).  The castles are on hills but everything around them is pretty flat.  The Eagle's nest is in beautiful, beautiful mountains.  The castle is beautiful but you'll have to walk it with the kid.  There are like 200 stairs up on the tour.  It was nice but if you're in the area, I would do the Eagle's Nest (that is hugely touristic and a pita to get to, but completely and totally worth it in my opinion).  Also, when you're in and around Salzburg, there are random ski lifts everywhere that will take you up for beautiful views.  I cannot remember what they are called to save my life but we found them in just about any tour book we read.

This sounds like a lot to do in 4 days - I don't feel like you'll get a great feeling for either Munich or Salzburg with the amount of time you've got there.

Fussen (where Neuschwanstein is) is gorgeous - but it's definitely a full day trip, which means you're looking at a half day in Munich total.

You're also looking at less than a full day in Salzburg given this itinerary.  And I could spend a week in Salzburg alone - it's one of my favorite cities in the world.

If I were doing this trip, I would pick one area or the other and spend the entire 4 days there - either a trip to Munich (with a side daytrip to Fussen) or a trip to Salzburg.  Bavaria, where Munich is located, is more similar to Salzburg than other parts of Germany (from what I've been told) so you may very well like it.

Salzburg is beautiful. You might do the Sound of Music tour.  The tour drives through some amazing scenery - lakes/mountains/adorable houses, etc.  The toddler would like it because there is singing on the bus and places to get out and walk around, without TOO much walking.  :)  If you are a fan of the movie you shouldn't miss it. Just walking around the town of Salzburg (and getting an amazing dessert in one of the cafes) is charming, too.

There is the lovely Nymphenburg palace in Munich with gardens that you would all probably like.  

Neuschwanstein is cool and so is the right-next-door Hohenschwangau castle.  Get reservations ahead of time. You'd have time to do these castles in the morning and get back to Munich in time for dinner (at the beer halll!)

Berchtesgaden National Park (containing Lake Konigssee) is a beautiful, gorgeous park right on the way from Salzburg to Fussen.  If you like mountain scenery, that's the place.

 

We spent four days in Munich/Salzburg last summer, and found that to be enough time to see Munich, but not enough for Salzburg. We spent a day doing the castles tour (this really does take a day, considering it's a bit of a trip from Munich), then spent a day exploring Munich. The Salzburg tour was another full day, and I wish we'd had more time to spend there (we also we spent the remainder of our 2-week trip in Italy, and Salzburg was the fist city I'd go back to, if we're ever back in that area). The last day was more Munich, a couple of museums in the morning and a our of Dachau in the afternoon.

It might be easier to use the train than to rent a car, unless you need one forr another reason. It's a pretty easy and fairly inexpensive trip from Munich to both Neuschwanstein and Salzburg on the Deutsche Bahn.

Obsession:

OK and if you like mountains, I would go to the Eagle's Nest before I went to Neusweinstein (I can't spell it to save my life).  The castles are on hills but everything around them is pretty flat.  The Eagle's nest is in beautiful, beautiful mountains.  The castle is beautiful but you'll have to walk it with the kid.  There are like 200 stairs up on the tour.  It was nice but if you're in the area, I would do the Eagle's Nest (that is hugely touristic and a pita to get to, but completely and totally worth it in my opinion).  Also, when you're in and around Salzburg, there are random ski lifts everywhere that will take you up for beautiful views.  I cannot remember what they are called to save my life but we found them in just about any tour book we read.

thanks for all the tips!  Obsession - when you mentioned the 200 stairs - is that at Neuschwanstein or the Eagle's Nest?  can't imagine carrying DS that far...!  we are thinking of skipping Neuschwanstein & heading straight to Austria on Day 2, then head back to Munich on the last day - spend the day there & fly home then.

valeivegas:

Obsession:

OK and if you like mountains, I would go to the Eagle's Nest before I went to Neusweinstein (I can't spell it to save my life).  The castles are on hills but everything around them is pretty flat.  The Eagle's nest is in beautiful, beautiful mountains.  The castle is beautiful but you'll have to walk it with the kid.  There are like 200 stairs up on the tour.  It was nice but if you're in the area, I would do the Eagle's Nest (that is hugely touristic and a pita to get to, but completely and totally worth it in my opinion).  Also, when you're in and around Salzburg, there are random ski lifts everywhere that will take you up for beautiful views.  I cannot remember what they are called to save my life but we found them in just about any tour book we read.

thanks for all the tips!  Obsession - when you mentioned the 200 stairs - is that at Neuschwanstein or the Eagle's Nest?  can't imagine carrying DS that far...!  we are thinking of skipping Neuschwanstein & heading straight to Austria on Day 2, then head back to Munich on the last day - spend the day there & fly home then.

The castle is 200 steps.

To get to Eagle's Nest, you get on a bus, then ride  an elevator, then walk.  It was pretty rough up there so no stroller but you could definitely Ergo the kid or let the kid walk (if a 16 month old walks I can't remember).  Amazing views.