has anyone gone to Burghausen Castle?

Yes, it's an interesting place to visit. I recall using the train only and walking from the station. I don't think my day began and ended in Munich, however, which would mean 5 hours of round-trip travel, which is too much time for any day trip, IMHO. Munich is a weak base for day trips if castles are the objective. Will you be elsewhere in Germany? Nuremberg isn't too far, and the Imperial Castle there might be interesting to visit in addition to Nuremberg's many other offerings. The ICE will get you to Nuremberg in just over one hour.

The castle and town itself were well worth a visit for me. I was nearby at the time. A five hour return trip? Not for me; I'd say the same for almost every place I've been. If a train ride itself was to be very scenic, which in this case it isn't, then maybe.

Not a castle, but Nymphenburg is in town. Schleissheim is fairly close.

I visited Burghausen in 2007, as I was making my way back from Passau to Munich. Yes, it was interesting, but I was passing right by it. I don't know that I would make a trip from Munich to visit it.

The reason that it is called the longest "castle" in Europe is that the original castle was built at the end of a long peninsula of high ground above the Salzach river. The castle was built out on the end of the peninsula, then they built a courtyard to protect the castle, then another courtyard to protect that courtyard and so on until they got back to the beginning of the peninsula. Something like nine courtyards in all. The sides of the peninsula were really too steep for an assault from the side, so any assault had to start a km away at the base of the peninsula.

Yes I think it is worth a visit. I have taken Family there and stayed there for a weekend once. I drive and pass through Burghausen when taking secondary roads back and forth from my home in the Oberpfalz to Austria. The border was always open even during Covid. I've visited mostly in summer and there was 1-2 cafe within the castle walls. Nice areas to walk along the Wöhrsee and the Salzach. Good view of the castle from Berchtesgadener Str. when driving by. We visited nearby Kloster Raitenhaslach too.

Thank you everyone as you gave me a lot of great advice.

Fwiw, yes, use of all caps should be avoided because of it's interpretation online as yelling. Other formatting options like bold or italics can be used for emphasis. It's just an etiquette thing and it help to avoid side topics like this. It's not in the guidelines as we have technical limitations on overuse which handles most of it.

We've cleaned out the side discussion on that subject in the interest of keeping things on topic for the OP.

Thanks in advance for any further information about Burghausen Castle.