After reading about the Eurail Pass...I still want to make sure I understand one point correctly. Our travel plans are during Christmas Market time. Right now we are aiming at Frankfurt being a base for part of our time. Using Frankfurt, we would travel as day trips (meaning round-trip Frankfurt to for example Heidelberg, Cologne, Stuttgart, Dusseldorf). After Frankfurt we travel to one way to Strasbourg for a few days and then finally one way to Basel for a few days. Am I correctly understanding that since the Eurail pass is 'unlimited,' it would include our round-trip travel as well as one-way directional travel? I see nothing that prohibits round-trip travel, but so much of Eurail is described as traveling throughout various destinations from one point to the next.
Also, we also are looking at a Frankfurt to Bacharach day trip, but it appears that the Eurail would not qualify for that trip due the train is a regional carrier. Is this correct?