How clumsy of me to destroy the airport codes but you correctly identified my destinations as I fly DL and those cities are their primary choices so I amended the OP.

I saw some the schedules on the Iban web but don't know anything about the changes for trains from say FRA or STR. I carry a lot of international luggage and have always struggled in Europe when changing trains in small stations - some but not all have belts to help me get up and down the stairs - much less getting a seat where I can manage the luggage for that matter.

My biggest problem came about a year ago when I landed at FRA and went to Heidelberg. I forget where I changed trains but I got in the rear cabin and only just before the train departed learned that part would break off and go in the wrong direction so I ran to the front of the train. I just haven't mastered reading signs especially when you get away from the metros and don't have much connection time and not as much info posted.

Updated to say that - since I didn't do my homework - I just noticed one schedule from FRA has three changes but most are only 1 yet the fare is much higher than STR. I can fly from STR to MUC for about the same price as taking the train from FRA. If I bought the ticket today, ExpertFlyer talks me I would have to use STR to get the z inventory for my M/B fare (OKC-ATL-STR then back home from IST). So that then makes me wonder about how much taxi fare I would save to simply arrive in STR on DL then take Luftansa to MUC and a train on to Pullach.