Munich, Vienna, Prague, Budapest

https://community.ricksteves.com/travel-forum/austria/vienna-prague-budapest-trip
https://community.ricksteves.com/travel-forum/to-the-east/vienna-prague-budapest-0f5fb7ba-dcec-46fd-9147-7b913a91074b
https://community.ricksteves.com/travel-forum/czech/logistics-of-vienna-prague-and-budapest
https://community.ricksteves.com/travel-forum/austria/vienna-salzburg-prague-budapest-itinerary-request-for-suggestions
https://community.ricksteves.com/travel-forum/hungary/prague-vienna-budapest-what-order
https://community.ricksteves.com/travel-forum/czech/april-trip-to-london-prague-vienna-bratislava-and-budapest
https://community.ricksteves.com/travel-forum/general-europe/opinion-on-order-of-travel-budapest-vienna-prague
and so on from here
https://search.ricksteves.com/?button=&date_range=2y&filter=Travel+Forum&page=1&query=Vienna%2C+Prague%2C+Budapest&utf8=%E2%9C%93

The best place to buy train tickets generally is from the company of the country from which you are departing. That means, in this case, you are not going to be able to one-stop-shop for tickets.

You have 15 days. It all depends on what kind of travel you enjoy, so I won't say your idea isn't too much. But let's say you wanted to see the most iconic sights in each stop. My take on it would be, in full days:

Munich 2
Prague 2
Vienna 3
Budapest 4

Without travel time that's 11 days. Arrival in Munich 1 day, to Vienna 1 day, to Prague 1 day to Budapest 1 day = 15 days total.

So, in theory it works. If you add a day in Salzburg, take it from Vienna or Budapest after you research the 2 and decide which speaks loudest to you.

I would say train Munich to Vienna, train Vienna to Prague, fly to Budapest.

Actually, I would skip Vienna and do Salzburg and an overnight trip from Prague or Budapest (Eger), but that wasn't your question.

And, yes, buy your tickets from the primary carrier in the Departing country.

Thanks. I definitely plan to take it from Vienna. That wasn’t originally on my list, but my husband really wants to go.

Also, thanks for the flying recommendation. That was my first thought but everything I’ve read says that takes as long in the long run so you might as well enjoy the scenery (is it that impressive?). I’m also only seeing one flight per day? That seemed odd to me.

This past December as part of a tour of Christmas markets we travelled Munich-Salzburg-Budapest-Vienna-Cesky Krumlov-Prague, all by train except for the Vienna-CK link. That was the most efficient route for our plan, as we needed to finish in Prague. Your plan would work fine, although it connects the two most distant points, so a stop in between would be a good idea. Munich to Prague by train takes about to same amount of time as Munich to Budapest, but spending some nights in Salzburg cuts about 90 minutes from that trip as Salzburg is on the route. As for your husband’s wish to drive, maybe he should rent a car in Salzburg and drive around in the mountains for a day to get it out of his system. You definitely don’t want or need a car in any of the cities you are visiting. (Better still, forget about the car entirely.)
I have sometimes used Trainline to purchase tickets on previous trips, with full satisfaction. However for this trip I used the websites of the national railways of the country that operated the train. Bahn.com is a good site to check out routes in most of Europe, and I bought the tickets for the Munich-Salzburg trip from them. I used the Austrian site, OEBB.at, for the two trips between Austria and Hungary, and cd.cz for my local train in Czech.

Thank you!
The idea was renting the car in Salzburg and returning it same day in Vienna. We’re only interested in maybe stopping in Salzburg for a couple of hours and I figured it was an easy way to avoid renting and dropping off in a different country while still letting him drive.

I was on the fence if it made more sense to do Munich->Vienna->Budapest->Prague or keep our current itinerary. I need to look into Munich-Budapest-Vienna-Prague now. Didn’t even think about that route.

everything I’ve read says that takes as long in the long run so you
might as well enjoy the scenery (is it that impressive?). I’m also
only seeing one flight per day?

It will save you at least 3, maybe 4 hours. But it's as much about do you want to be trapped on a train with no great views or at least be moving around, a restaurant, shopping?

https://community.ricksteves.com/travel-forum/czech/prague-to-budapest-transportation-options

Tuesday snd Thursday there 2 flights, none on Sunday.

Read this too. https://community.ricksteves.com/travel-forum/czech/trip-from-prague-to-budapest

Keep in mind that Budapest and Munich are connected by night train if you want to consider that option, an option I probably will end up doing this coming trip in May.

If cutting Prague is an option I would consider it to reduce running around; the other cities make a nice line and you could add time to Salzburg.

I guess I was spoiled by the French/Italian/German high speed trains because I found my experiences with the Czech trains to be subpar. Old and slow and late, aisles so jammed no chance of using the toilet much less getting food out of the dining car, missing cars so paid for seat reservations nonexistent. I wouldn’t do Prague Budapest in the summer by train again, and that was in first class.

We actually made the decision today to cut Prague out since no travel option was really desirable. We’re going to spend those extra days around Romantic Road and Salzburg instead. That way he gets his car driving time in and it’ll be a little more relaxing.

So, Munich, Salzburg, Vienna, Budapest. Sounds like a great trip.