Germany train or rental car

Most trains departures require two connections on this route, or a few with only one connection. Are you talking about a same-day roundtrip, without luggage? Or staying longer and possibly keeping the car for additional stops, cemeteries outside of town, etc? It's usually cheapest to pick up and return the car within one country, but Strasbourg is so close to the border that fees might be minimal.

I sent you a PM.

You may already know this, but in case you don't. In terms of the family grave sights, you may want to contact the church, cemetery, or town first to make sure that the gravestones are still there. I know that sounds strange to our American ways. In Germany space is limited for graves, so for many places the family pays for the grave every so often (I think we were told the family pays every 5 years) and when the money runs out, then the remains are moved and someone else is buried in the plot. I know my dad was disappointed when we were in a town where my ancestors lived and he couldn't find grave stones for them. This may not be the case for you, but it never hurts to check first.

I suggest taking the train from Strasbourg, transfer in Offenburg to Heidelberg. Rent the car in Heidelberg, even though public transport connect Eberbach and Heidelberg.

Susan K. is correct about grave sites. In 2013, my son and I walked all over a cemetery looking for my great grandfathers grave. I remember visiting in 1969, but in 2013 I couldn't find it. That evening I spoke with my mom back at home and she told me that the grave was removed years ago since there were no family members left to maintain and pay for the grave.

The rules for removing graves in Germany are different in every village, town and city. The rules are set up by the local councils and they can be changed, of course.