Munich airport to Fussen and castle in one day, is this doable or just insane?

It’s possible if your flight is on time. Are you flying in from the USA?

yes, thanks. From Houston, Texas to Munich

Looking at the schedule, you could leave the airport as late as 13:44 on the S-8 and get to Fuessen by 16:45, then stash you luggage in a locker and catch the 17:05 bus up to the castle, arriving at 17:13. So that gives you a 3 hour cushion at the airport to get off, clear immigration, get your luggage and make your way to the airport train station and buy your 9 EUR ticket. That ticket will cover the return back to Munich next day.

Obviously, if you can get to the train station by 11:44, you will have time to check in at your hotel.

Taking the S-8 at 13:44 rather than the S-1 at 13:51 per the DB website saves you one train change from Munich Laim to Munich Pasing.

After you're out of baggage and security and have made your way to the MUC rail station, the train journey from the airport to Füssen requires 3 or more different trains. You're taking your bags with you of course on this trek. Then you head to your hotel on foot to check in, and then to the nearest shuttle bus stop for a bus ride from Füssen to the ticket center bus stop. And after that, another bus ride back to Füssen, of course, after your 30-minute tour, with 2 trains back to Munich the following day. This train+bus transport alone takes between 4.5 and 5 hours round trip. Did I mention that on top of this, you have a long uphill walk from the "Castles" bus stop to the Neuschwanstein entrance of 40 minutes or so?

It's really hard to plan so tightly around a flight arrival time that might come significantly later than planned. If you're like me, after a red-eye transatlantic flight, you will be somewhat eager just to get to your room, get rid of your bags, get a shower, maybe get some walking in and some food somewhere. I would take care of all that in Munich first. Any long journey into the Alps would take place on another day, or not at all, and would probably be made for other reasons besides the 30-minute tour of N'stein. It's is an interesting and unique building, but it's of no particular significance, to be honest. In the late 19th century, Ludwig II spent outrageous sums to have it built, used it as his royal residence for 6 months, and then the biggest event that ever took place there happened... Ludwig promptly expired for undetermined reasons.

All that said, I've heard of crazier efforts than the one you have in mind to visit the place.

If the stars align, then it's doable. But consider that you will be rushed, jet lagged, rushed, anxious, and have I mentioned jet lagged. And no where did I see mention of taking time for a meal. Would you consider just travelling to Fussen, checking in, and seeing the town on your arrival day, and then seeing the castles the next morning, before returning to Munich? Seems less stressful to me.

Just nuts-IMHO

Our last two international departing flights [post-covid] have been significantly delayed- one was canceled entirely, and we had an unanticipated 24 hours in Chicago. Our recent April flight was delayed 4+ hours [pilot tested positive for covid], so we missed our connection flight; finally arrived at our Munich destination around midnight.

So nuts because you have no idea if you'll actually arrive in Munich on time, and nuts just because my own trip to Fussen and the castles [pre-covid] was one of the most exhausting travel days I have ever experienced. Even with timed tickets, there are lots of lines -in the heat- and lots of walking. It is very commercial, crowded, and frankly, IMHO, the 30 minute tour just isn't worth the work.

If you must, I like the suggestion to just get yourselves to Fussen the first day, and see the castles the next day.

Good luck!

Thanks for all of your input. It makes sense not to rush things. Another thought is to do Howenschangau the following day, as there are English tours earlier in the day. We could head back to Munich in the afternoon. The day of our arrival in Fussen could then be more relaxing and we could recover from the flight and train ride on the 23rd.
Thanks again for your thoughts.

I like your most recent plan better....

Thanks Nigel, so does my wife!

Flying in to Munich and trying to see the castles the same day is INSANE.

I think you should spend one day flying into munich and traveling to Fussen.
Then spend the second day seeing both castles.

We spent one day seeing both castles last week. Here's the schedule we had (to show it can be done):
We had 10:50 am tickets for Neuschwanstein and 2:30 pm tickets for Hohenschwangau

9:00 take bus from Fussen to Castle Visitor Center. Arrives around 9:20 or 9:30
Walk to shuttle bus stop at far end of staging area.
10:00 take shuttle bus up to drop off point for Neuschwanstein . (cost €3.50 each, one way)
Or you can spend 40 minutes walking up the steep hill to the castle.
Walk down from drop off point to castle entrance : 15-20 minutes. Depends on how fast you walk and how many times you stop to take pictures.
10:30 entrance to the inner courtyard. A guard looks at your tickets.
10:50 Timed tickets. The electronic gates say when to enter.
Did 30-45 minute English tour of Neuschwanstein. 15 minutes more in gift shop and balcony to take pictures.
Exit castle and walk down locker/visitor area. Take more pictures
Walk down past restaurants to horse carriage stop.
Take horse carriage down to visitor's center. (€3.50 each) Or you can spend 30-40 minutes walking down the hill.
Noon: Eat lunch at one of the crowded restaurants.
2:00 pm Take horse carriage up to Hohenschwangau (€6.50 each)
2:30 pm Tour time entrance. The electronic gate says when to enter. We did the English audio tour. What happens is that X number of people are allowed in at the tour time led by a guide. Every person has an audio tour in their language of choice. At each room, the tour guide activates the audio guide for that room. Then afterwards moves on to the next room and the action is repeated.
Tour takes less than an hour.
After tour, walk down the steps to the visitor centers (15 minutes )
Walk to the bus stop and take the bus that goes back to Fussen.

So you can do both castles in one day, if you have reserved tickets and time it right.

Hope this helps you decide how to plan your trip.

Thanks Derek,
thanks again to all for a sanity check. I think I've got it figured out for a more leisurely visit.
We arrive in Fussen on the day we fly into Munich, then relax in town. The next morning we take it easy and take a 2:30 tour of Howenschangau. The only audio tours for Neuschwanstein are 9am or much later in the day, so we'll blow off that castle and just appreciate it from a distance. Back in town, we'll gather our luggage and make the trip back to Munich later in the afternoon.
Glad for everyone's help.

Derek, you've done a very fine job of describing the realities of visiting that area. Is St.Mary's Bridge still closed?
Thanks again.

Yes, Mary's bridge is still closed.