What to do on drive from Garmisch to Munich for a full day
 

I'm helping friends plan a trip after their cruise. They've got a full day to drive from Garmisch to Munich and I'm looking for suggestions. I was hoping to get them over to the Black Forest and some of the outdoor historical towns there but I think that's too far out of the way. If you had a day to make this drive...what would you see along the way. They'll be a family of 4 (2 adults/2 teenagers) who have traveled thru Europe several times before.

They'll have already spent two nights in Garmisch and seen the castles and the Zugspitze. They'll then spend 2 nights in Munich just wandering the "old" downtown city center and seeing the sights. I think they'd prefer to spend this day getting into the countryside vs. spending any more time at Garmisch/Munich. One thought had been going over to Lake Constance...but even that might be too far west as it seems they'd spend half the say driving.

Thanks

Visit Herrenchiemsee? Or Weiskirche followed by Andechs?

((B))

Which castles will they have seen, exactly, of the four total?

I was going to suggest Herrenchiemsee but they may very well have become palaced-out by this point and after two days IN Garmisch?

The Koenigsee perhaps? Do we know of their interests at all?

They'll be seeing Hohenschwangau and Neuschwanstein. Depending on the time they spend on top of the Zugspitze and at Neusch they may drop Hohen.

Herrenchiemsee does look like a great thing to see. I'll put that on the list. Are there any natural things to see in the area...great hikes, beautiful lakes, etc?