Do you have a car or do you rely on trains/busses? After your answer, I'll be glad to give you a few suggestions. If you rely on public transportation, in the meantime plase read up on "Bayern Ticket" in the Search part of this forum.
I have a vehicle I am visiting from Heldelberg..
Then Oberstdorf, Lindau , Friedrichshafen , Meersburg can all be on your itinerary. Also Bregenz ( via Bregenzer Wald and Dorbirn - all Austria) and St.Gallen (Switzerland) area are doable. Fuessen is doable, but a bit of stretch all in one day if you want to see the inside of the Neuschwanstein castle. How old are your kids? The castle tour, because of its length and long narration, is a bit hard onyoung kids. But the outside view of the castle is great .
This is great information! We went to Bregenz yesterday! We to the cable car to the top of the city and took some beautiful photos! Since it is Christmas day here today, we probably will not venture out too far for fear of attractions not being open. We will attempt to do Meersberg tomorrow.. The Castle looks great! Then, we will head to Switzerland!