Most efficient travel within Germany

Rail will be the most efficient way. Look up schedules on the Bahn website. Note how Rothenburg odT is spelled. If you use the wrong spelling you could end up somewhere entirely different.

How many people are "We", what are the ages, and how many days of travel is this? Are you traveling two days and spending a night in Rothenburg or doing this all in one day?

I'm assuming two adults. If all in one day, you should use a Bayern-Ticket, 31€ for all your travel. If you are doing this in two days, use a VGN (Nürnberg metro) TagesTicket Plus (Price Level 10, 19,10€ for 2 adults) from Nürnberg to Rothenburg and the Bayern-Ticket the next day.

The VGN TagesTicket is valid all day long. The Bayern-Ticket can only be used after 9 am weekdays, but all day long on weekends. Regional trains only.

Thank you so much! It's just two adults and we would start in Nuremberg, spend 2 nights there, then on to Rothenberg odT, spend two nights then Munich for a few nights.

Rothenburg ob der Tauber and Nuremberg are both in the Greater Nuremberg transit district, so you can use a VGN Tageskarte Plus for that. Travel after 9 am weekdays (any time weekends). It's in the 20 EUR range for 2.
Rothenburg to Munich, use a Bayern Ticket. 31 EUR for 2, regional trains only, like VGN, after 9 weekdays.
Munich to the airport is a local S-Bahn ticket.

Personally, we love to drive, and the driving is super easy & efficient where you're headed. A little over an hour to Rothenburg ob from Nuremberg. Maybe from there stop in Fussen? We absolutely love Fussen and it's great for a night stay or two. It's a little over two hours from Rothenburg and the scenery along this stretch of the "Romantic Road" is beautiful. From Fussen to Munich is 90 minutes or so, and it's one of our favorite drives in Bavaria - just absolutely breath-taking.

"It's just two adults and we would start in Nuremberg, spend 2 nights there, then on to Rothenberg odT, spend two nights then Munich for a few nights."

Lee has you up to speed on the train trips for your stay as planned. I would just point out that Rothenburg actually does not require a lot of time - one day is adequate, I'd say. It's relatively small and can easily be done as a day trip from Nuremberg (and it often is.) With the VGN ticket Lee mentions, you can do the round trip Nuremberg-Rothenburg-Nuremberg and pay nothing extra since the VGN Ticket is actually a day pass. Booking in two places (Nuremberg and Munich) rather than three means less luggage fuss and less check-in, unpack, pack-up, check-out routine. That might be appealing to you.

One additional advantage of the VGN ticket is that if bought for Saturday travel, you can use the same ticket on Sunday as well for another day trip somewhere else. And whether it's the weekend or a weekday, nearby Bamberg might be that somewhere else. Bamberg, one of Germany's UNESCO World Heritage cities, is less than one hour from Nuremberg by direct train. Nuremberg was mostly rubble in 1945, but Bamberg though damaged, has one of the country's best preserved medieval town centers. Though Rick Steves book ignores it, I have no idea why - it's a major player in most other guidebooks and IMHO much more interesting than super-touristy Rothenburg.

Perhaps 4 nights in Nuremberg with a day trip to Rothenburg and another day trip to Bamberg would give you a more complete picture of Germany. Then see Munich after that.

I want to add a few comments to the above posts.

First, on my first trip to Rothenburg I made it as a day trip from Ansbach (closer than Nuernberg). That time I left in the early evening feeling I had seen Rothenburg.

The next time I spent two nights in Rothenburg, arriving mid afternoon on the first day and leaving on the morning of the third day. We had the first afternoon and evening to orient ourselves and the entire day in between to really explore the town. I feel that I saw a lot more of Rothenburg the second time, but not too much. We spent a lot of the full day walking the wall on the Wehrgang, including four of the gates, then spent some time in St.-Jakobs-Kirche, with the Riemenschneider Altar. We had two delightful dinners in Rothenburg. If you use the time effectively, two nights in Rothenburg is not too long.

Second, a lot of the experience of being in Europe is doing things you can't do at home. Driving is certainly not one of them. It is so much fun to use an effective system of public transportation. It's far less expensive than renting a car, and you can see so much more from the train since you are not driving.

And the Romantic Road is just one of many country lanes in Germany, two lane and curvy, if not winding. Except for the designation, it's very ordinary. I did the "Road" in 2007 entirely with public transportation. Some of it was by train, but a lot was by bus on the very same road you would travel by car. At one point we came back to the Road after a stop in one of the nearby towns and had to wait at the intersection while a lorry went by followed by about 20 cars that couldn't pass. And this was in October, hardly the height of tourist season.

I am a fan of Rothenburg. We are going back for 2 days in April. In addition to what Lee mentioned, I like a Riemenschneider altar in the Franciscan Church, the Reichstadt Museum for its landscape paintings and walks into the valley.

We had our own car for 6 years in Germany and it was good to drive there. I have rented a car one year for visit since, and then for the next 13 trips we have taken the train. For me it is more pleasurable to use the train system and let someone else do the driving. Visiting towns, it is nice not to worry about parking or traffic. I can see both points of view but we are taking trains in April.

Have a great trip in either case.