Help with 9 day itinerary: car or train?

A car would be a major pain in Munich city, so I would rent when leaving town and be sure to buy a short term Austrian vignette sticker and attach it to the windshield in the proper spot. I think they are only about 10 EUR and then you can drive on motorways. Available at gas stations near the border.

Neuschwanstein is best driven from Garmisch. There are other sites along the way, like Oberammergau (although the Passion Play will be going on with possible traffic/parking issues) and Schloss Linderhof.

We've made a southern loop out of Munich a number of times. You could take in Newschwanstein/Fuessen before heading to Garmisch and then a short drive down to Innsbruck. Then you have controlled access roads all the way to Salzburg, or you could take a more mountainous route.
The scenery in the Austrian Alps is truly breathtaking.

"If I chose to drive, would I need to pick up the car as I leave Munich or should I get a car from the airport and use it for day trips?"

It's not clear what other day trips you have in mind (if any) besides N'stein (from Garmisch.) If you want a car for that day, you can rent it and return it in Garmisch. There are also buses from Garmisch to N'stein, for which you'd likely pay around €10/person for a day pass. If you want a car for one day in Salzburg, I imagine that's a possibility as well.

I don't see much value in renting the car at MUC for 9 days, then driving into Munich and later on to Salzburg and Garmisch so that you can park the car there at your hotels for most of 9 days. These places are all well served by trains, and they are inexpensive trips as well with 5 people traveling together. Munich and Salzburg are both a pain with a car, IME. And Garmisch has train and bus connections of all sorts nearby (and local transport is free of charge with the Guest Ticket you get from your Garmisch hosts.)

Garmisch region train and bus routes: https://bahnland-bayern.de/files/media/bahnland-bayern/tickets/regio-ticket-bayern/Regio-Ticket%20Werdenfels/BEG_GR_Regio-Ticket_Werdenfels_2016-09-Ansicht.jpg

Munich, Salzburg, and Garmisch-Partenkirchen, as well as Füssen (Neuschwanstein) are all conveniently connected by public transportation. The best connection from Garmisch-Partenkirchen to Füssen is by bus, the others are by rail. Rail and bus travel can be accomplished using a Bayern-Ticket (or sometimes a less expensive regional pass), an all-day (after 9 AM workdays), unlimited travel pass. It cost €53 for five people traveling together. For your itinerary there would be no need for a more expensive car rental.

I have, by the way, been to all of those places, plus plenty more in Bavaria, using only public transportation.

Think about what kind of vehicle you will need for five people and all their luggage and how much it will cost to rent.

It's more expensive to rent a car at the airport because car rental agencies pass on an airport tax. After checking your destinations on www.bahn.com, you can take direct trains to all places that you're going so why rent a car.

Certainly no car for the days you are in Munich. Maybe not for Salzburg, depending on what you plan there. Getting a car over the border from Salzburg and driving to G-P is not a bad idea.

+1 for stephen

Good morning,

Thank you for all your input. I enjoy taking public transportation and considering the size of cars in Europe and the luggage aspect, (and a tight squeeze for the back passengers), I think we will do the rail/buses option. I just wanted to make sure this was doable with my itinerary and I am am sure having a car in the Cities will mean I will just have it parked somewhere. If I feel like I need a car - I could always rent in Garmish. Other than that, I can also find 'tours" for day trips out of the cities.

Margaret