Help with travel

For train connections check https://int.bahn.de/en

3hrs from Frankfurt Airport or Main Station in the City to Rothenburg ob der Tauber
Change trains 2 times in first Würzburg then Steinach

Hope its that Rothenburg you want to go to there are several in Germany

This is a train trip. Two important questions for you:

Will you be using the Deutschland-Ticket (€58/1 mo. of unlimited travel on regional trains) for your travel in Germany?

Will you be traveling to Rothenburg right after a flight arriving at FRA airport?

Yes we will be traveling to Rothenburg ob der tauber. Our flight arrives on the 1st of May at 7:20am.
We are staying in Rothenburg for 4 days. Then we will train back to Frankfurt and catch our flight into Venice.

How you get to Rothenburg depends on your tickets.

Full-fare "Flex" tickets can be bought in advance or at the station; price is around €120/2 adults. They are refundable if bought in advance and can be used at ANY time that same day on the route to Rothenburg.

"Saver Fare" tickets, which are train-specific and non-refundable, are available for purchase now at DB and range €70-85 / 2 adults. Prices go up as tickets sell.

Both ticket types require that you ride 3 separate trains. You ride a long-distance (high-speed) ICE train from the airport's "Fernbahnhof" (1 of 2 stations there.) You get off in Würzburg and then ride a regional train to Steinach, then change there to a final regional train for Rothenburg. The trip takes roughly 2.8 - 3.25 hours depending on your departure time.

May 1 schedule: A 3-train sequence with a change in W'burg and another in Steinach:
Lv FRA 8:35 / 10:01
Ar R'burg 11:51 / 12:51

The Saver fare ticket is probably inappropriate since you cannot predict flight delays or lines at security and will forfeit the ticket if you are unable to travel as your ticket dictates.

The other option:

The Day Ticket For Germany is priced at €49/2. It is the same price no matter when you buy it. It is non-refundable, so it's best to buy it on the day of travel or the day before. It is valid for a full day of train travel anywhere you like, on regional trains only, which means you use a different train station at the airport - the "Regionalbahnhof." You will have one additional change of train for this journey at Frankfurt's main station... First, you ride a regional train to Frankfurt Hbf station (around 12-13 minutes.) Then you ride a 2nd regional train to Würzburg, then a regional train to Steinach (as before) and a final regional train to R'burg (as before.) The journey takes roughly 3.8 hours altogether. You can leave FRA every hour on the hour depending on when you exit security, and the schedule will be approximately the same as what you see below:

May 1 schedule:

Lv FRA 9:00
Ar Frankfurt Hbf 9:13
Lv Frankfurt Hbf 9:30
Ar W'burg 11:21
Lv W'burg 11:41
Ar Steinach 11:41
Lv Steinach 12:23
Ar R'burg 12:51

Thank you so much Russ. You are a wealth of information. You explained things perfectly. I truly appreciate your help.
Deb