Fussen to Bozen

Although the Austrian border is tantalisingly close, Fussen is actually at the end of a branch line, so that pretty much obliges you to go via Munich. From there you can get a Eurocity service all the way to Bozen/Bolzano in just under 4 hours. It stops at various stations in Austria, but I assume you mean your pass just doesn't allow you to alight or change trains there. If you have to buy a separate ticket for Munich to Bozen and can book a couple of months ahead it will only cost €29, or around €60 on the day.

Try googling "bus Fuessen to Bolzano". Rail conections stink. 6 to 8 hours, but it would only be about 2 to 3 hours on a bus.

If you have a multi country Eurail pass (I assume that's what you mean by "euro pass"?) it will not allow transit through un-named third countries regardless of stopping off the train or not, and regardless of whether or not the train actually stops there. The only exception that I know of is the train between Innsbruck and Salzburg Austria which uses a non-stop "corridor" which goes through a chunk of Germany to do an end run around some mountains which are in the way. You may have heard of the Alps? That's what causes them to use the corridor. By train, the only way I know of directly going between Munich and Bozen/Bolzano is through Austria and if you use the train you will have to buy a point to point ticket for the Austrian segment. Maybe the suggested bus would be better. dunno.

Maybe the suggested bus would be better. dunno. Me neither. I spent 15 minutes with Google, trying to find a direct bus before I gave up. The best I could come up with was a bus from Fussen to Reutte, then two buses to get to Innsbruck, a train from there to Brenner and then another train to Bozen/Bolzano. Or at Innsbruck get the Eurocity train I mentioned before that comes down from Munich. Total journey time at least 5 hours 15 minutes and probably more, given there are only 4 buses a day from Fussen to Reutte. Sam, it remains to be seen whether the OP ever comes back to the thread, but do you have any specifics about bus services?

I think you are out of luck. Most sensible way would be 7 am train to Munich with a connection at Buchloe, then change to an EC train direct to Bolzano. Advance purchase for 39 euro. Takes 6 1/2 hours. The other way starts with a bus to Reutte followed by a series of local trains to Garmisch, Mittenwald, Innsbruck, Brennero, and finally Bolzano. 6 hours.