Day Trip from Salzburg

You could rent a car and go over to Hallstadt. You could also go just east to the Mathausen Concentration Camp just east of Linz.
Another option would be to go south into Tirol around Innsbruck to see The Alps as a day trip. I like to ramble from town to town in that region.
Many go to Berchesgarten to see the Eagle's Nest, which is now a restaurant on top of the mountain.

It's not off the beaten path, but the trip to Berchtesgaden is very easy and cheap by bus from Salzburg. On that trip you can go to Eagle's Nest which has a nice view and trails you can walk around on in addition to the restaurant. I believe there is also a museum, but I skipped that part. Also in Berchtesgaden you can spend time at Koenigsee which is a nice spot to visit. Very scenic.

On a good weather day, Herrenchiemsee castle. Also Munich is a feasible day trip.

Hi,

You can take the bus from Südtiroler Platz at Salzburg Hbf to Bad Ischl. When I was at Bad Ischl in May, I saw the bus going back to Salzburg.

I highly recommend taking your day trip to Berchtesgaden or the Salzkammergut. If I had to choose, Berchtesgaden would be the top pick for me. There Berchtesgaden area is quite small but there are still quite a few off-the-beaten path options (Hintersee, Jenner Bahn, Rossfeld Road, Salt Mine Tours, Almbachklamm, to name a few). Even the popular destinations (Boat trip on Konigsee, Eagle's Nest, Dokumentation Zentrum) are well worth the visit in my opinion and I prefer to avoid busy tourist spots.

If you do choose Berchtesgaden and Nazi history interests you check out www.thirdreichinruins.com. My husband found it fascinating during our week in Berchtesgaden.

I once made a day trip from Munich to Salzburg, so I expect it could be done the other way.

Herrenchiemsee, Wagingsee, or Reit im Winkl would be accessible in a day. Burghausen, the longest castle in Europe, is accessible via Mühldorf.

If you go to Berchtesgaden, take the bus (RVO 850, Watzmann Express) from the Hbf or other stops in Salzburg (eg, Mirabell Palace). Buy a BGL Bus und Bahn pass from the bus driver. It will cover the bus to Berchtesgaden, most of the buses in Berchtesgaden, and a return to Salzburg via the train through Freilassing if you stay late in Berchtesgaden (the last bus back is around 6 PM).

I would second Chris from canada, we spent time a week or so driving in Bavaria ( south of Salzburg) earlier this year and are already planning when we can go back. so much to see.

Thanks all for the helpful tips! Sounds like there are lots of great options. I'm thinking that we will do bus to Berchtesgaden and Konigsee and possibly another stop if time permits.