Rail travel: All-of-Bavaria tickets

Just where can I get on a Bayern Ticket, I don't really understand the arrows on this map.

Can I go to Frankfurt, Innsbruck or Stuttgart?

I don't know about that map but the paragraph about the bayern ticket on the website says you can go anywhere in Bayern plus Salzburg, Kufstein, and Ulm.

I used to use it when I was a student (oooh, long time ago!). I went to Frankfurt and had to pay something like €10 extra for the bit beyond Bayern. Same for Innsbruck.

Sometimes it's worth looking at mitfahrzentrale.de or other car-sharing sites, lots of people like to practice their english and it's cheap (I paid €6 to go to Nürnberg the other week).

Does the Bayern ticket cover all the underground routes also?

I know it does Munich but for example I was also in Nuernberg the other day and I wasn't sure if it was valid there too.

I believe it is valid for Nürnberg subway system as well.

Also includes the "Ausserfern Bahn" a line through Reutte in Austria that is only accessable from Germany at either end and to Lindau on Lake Constance by the route that also clips the State of Baden-Würtemburg - via Hergatz.

Tip: Easy to get undated ones in advance from MVV ticket machines!

Would you not have to stamp the undated ones somewhere though?
In order for them to be really valid?

I've just offered unstamped ones to the guard and they have date stamped them with their clipper thing.