I visited Ramsau last summer. Not much to do, a small town strung out along one road, but a nice base particularly if you will have a car. Berchtesgaden maybe better if no car. We stayed nearby at a little village called Hintersee, overlooking the lake of the same name, which would be lovely to see in winter with the high mountains behind it. You can walk around it and (in the summer at least) walk through the woods and along the river to Ramsau. The whole area is very beautiful, quite traditional and undeveloped, steep mountains but no ski resorts as it's a national park. In winter you could go on a boat trip on Konigsee and get the Jennerbahn cable car up to the viewpoint. I didn't visit Berchtesgaden old town but understand it's pretty. Salzburg is quite nearby too.