Is it possible to store your luggage at the train stations or possibly at the hotel prior to check-in in Munich, Fussen or Salzburg?
Take a look at https://www.bahnhof.de/en. It provides details on many German rail stations.
You would have to contact the hotel directly to find out.
And for link in #1 use correctly typed German place names: München, Füssen.
In the past, there have been lockers and a check room (for larger luggage and longer times) in the station in Munich, but with the current construction, I don't know if they are accessible.
Update: According to Bahnhof.de, the lockers are still accessible but the check room is not.
According to this website there are lockers inside the Füssen station.
use correctly typed German place names: München, Füssen.
You can also use Muenchen and Fuessen (the German Bahn website recognizes the ue combination as ü, etc.).
There is an historic basis for this); the umlauted letters were originally the letter (a, o, or u) with a superscript e, which meant that the tongue was forward in the mouth, like for e. In old German script, the e was two diagonal strikes connected and with serifs and looked basically like quotation marks, thus, for example, u" or o". To save space, printers eventually moved the marks over the top of the letters and made them dots.
Oh, Munchen and Fussen also work. It used to be if you entered "Fussen" on the Bahn website you would get a bus stop on Fussenstraße in some other town, but now, the Bahn has added what I call an "ignorance algorithm" that offers you a choice, including Füssen Bhf, on a drop-down menu.
Most hotels will let you leave your luggage there prior to check-in or after checking out. Have never heard of a hotel that wouldn't do this.
I agree with Ms. Jo, Have never stayed at a hotel that wouldn't store luggage either on arrival or on departure.
According to this website, the Salzburg Hbf does have lockers.
Type in "Salzburg" where it say "Geben Sie Ihren gesuchten Standort ein:", select "Salzburg Hbf", then "more information" and scroll down to and select "Schließfächer".
It says the lockers are in the passage by the entrance to the public toilets.