We are doing a 1 day trip from Munich to Rothenburg and staying overnight back in Munich. How many stops by way of train?
Since there are several train options, it would be best for you to check this out using this website. Click on "Plan Your Trip" at the top of this screen. On the next screen, under the picture of RS on the left, click on Deutsche Bahn. Then on number 1, click on their website. This will bring you to their screen where you enter your travel info. Your arrival city is Rothenburg ob der Tauber. You will get a listing of possible train trips. Select a trip and click on the far left arrow which will give you the "details". At the bottom of this listing you can click on "intermediate stops" which will show you all of your stops. You can print this off and take it with you so you know where to change trains and what the previous stops are before you need to get off. There is not a lot of time to deboard the train--you want to have your luggage ready and be at the door. Have fun on your trip.
There are almost hourly connections out of Munich using regional trains and making two changes (in Treuchtlingen and Steinach) in 3½ hrs. Rothenburg is a little out-of-the-way town and the best, (almost only) connections to it are by way of regional trains. You can make that trip, round trip, in a day, with only regional trains for €28 (for up to five people) with a Bayern-Ticket. Some connections using express trains go by way of Nürnberg and actually take longer.
Thank you Denise and Lee! This is extremely helpful.