Although I prefer Fischen, Berchtesgaden would also be a good choice. I was there first by myself for two days, then came back later with my wife for about 2 1/2 days. That would be a bare minimum.

Spend one day at the Eagle's nest (Kehlsteinhaus), have lunch there, then come down and tour the Dokumentation Center in Obersalzberg, at the foot of the Kehrstein.

A boat trip on the Königsee is well worth at least a half day. Be sure to go all the way up the lake by boat, then hike across the moraine to the Obersee (beautiful scenery).

From Berchtesgaden, you can also take the bus (Watzmann Express) into Salzburg for a day. Buses run hourly from 7 AM from the Berchtesgaden Busbahnhof (in front of the Hbf). I believe you can do the trip using an RVO Family Dayticket for €20.

Berchtesgaden is a good example of someplace you can go without needing a car. Buses are frequent. I have gone everywhere I wanted to go to in Berchtesgaden with the buses.

Stay in the town, near restaurants and shopping. The best way to the town from the Bahnhof is via the bridge over the tracks and up the path. I believe there is also a bus from the station to town (we always used the bridge).

As for Fischen or Oberstdorf, that is also a place where no car would be needed. Everyplace in Oberstdorf or Fischen is within walking distance of the bahnhof. It is a narrow valley; the train runs down the middle connecting the larger towns. There is bus service everywhere else.

If you go to lovely Rottach on the Tegernsee, take the BOB Bayerische Oberlandbahn, a regional train from track 33 or 34 at the Munich principal train station (Hauptbahnhof), it goes to the lake near Rottach, the Tegernsee where a bus waits to take you to Rottach. About 1:15 hr or a bit more. Departures about once an hour, like 9:42, 10:42, 11:05 etc.

We visited Burghausen last June and absolutely loved it! It has the longest castle in Europe and is fully accessible. The village is charming, quaint and friendly - and prone to having frequent festivals. They embrace artists and there are a number of studios and galleries there as well as shops. It is on the Salzach River bordering Austria and Germany. We stayed on the Austrian side in Ach, Austria at the Hotel Burblick. Our room hung over the river with a full view of the village of Burghausen. Full breakfast at hotel. Good restaurant next door and across the bridge in Burghausen. It was a 45-minute drive to Salzburg and the same to various lakes in the Alps, tram rides up mountains, beautiful!
I think you would need a car, though, to do the things you'd want to do. Burghausen is perhaps 1 1/2 hour from Munich, 2 hours maximum.

As far as Oberammergau is concerned, I am not sure what there is to see in the town, except for some houses with murals on them, but there is plenty to see in the surrounding area and you
definitely don't need a car there. Oberammergau is the hub for RVO bus routes leaving in three directions.

There is a 9:32 train from Munich Hbf to Oberammergau. It takes 1:48 with a change of trains at 10:29 in Murnau. All three of you can travel to Oberammergau for €27 using a Bayern Ticket.

Between 8 AM and 4 PM, there are approximately eight bus connections to
Garmisch-Partenkirchen; the trip takes 40 minutes. There are things to see in Garmisch, plus you can take the train to Mittenwald or Innsbruck. You can also go from Garmisch via the Ausserfernbahn to Reutte in Tirol or to one of my favorite towns, Pfronten-Ried.

There are three buses in the morning from Oberammergau to Hohenschwangau; the trip takes 1 hour 20 minutes.

If you want to see Linderhof and Ettal Monastery in one day, a bus leaves Oberammergau at 10:26 and arrives at Linderhof at 10:50 (In the winter, Linderhof opens at 10 AM). You can spend three hours at Linderhof, then take the 15 minute bus trip to Ettal. The bus from Garmisch-Partenkirchen
to Oberammergau stops in Ettal, so there are frequent trips back to Oberammergau.

Most of these trips can be made with point to point tickets, or you can use a Werdenfels day ticket (www.bayern-takt.de, click Englisch, click red box for Bayern Ticket, click on Werderfels-Ticket on left side). It would cost €10 each for you and your older son; your younger son rides free with you. The Werdenfels Ticket is valid for unlimited rides in the area shown at
http://www.bayern-takt.de/media/PDF-...ticketnetz.pdf all day long (after 9 AM weekdays). Oberammergau to Fuessen would require RVO-TagesTickets (Day tickets), €8,50 each for you and your oldest son, €5,00 for you youngest son. You might be able to use a Family Ticket for €20. The RVO bus routes are shown at www.rvo-bus.de; it helps to read German.

<<Spend one day at the Eagle's nest (Kehlsteinhaus)...
A boat trip on the Königsee is well worth at least a half day. >>

Unfortunately, the original poster will be visiting at the end of this month. The Eagle's Nest will be closed. Boats might be running on the Konigsee, but I'm not sure if this is a certainty.

At any rate, Berchtesgaden is a great town. And, its proximity to Salzburg makes it even more appealing.

You are correct. Kehlstein will be closed and the ships on Königsee run on a reduced schedule and don't go all the way up the lake.

I lost track of with whom I was talking and where they would be and when.

There are still a few things to see. The Dok Center is open five hours a day. There is the Salt Works and the Watzmann Therme, but all things considered, I don't think I would bother with Berchtesgaden at this time of year. If you want to go to Salzburg, stay in Munich and do it as a day trip with a Bayern Ticket.

However, I would still recommend Oberammergau or the Allgäu.