Bergbahn Heidelberg is the fastest and most convenicent way to get to the castle.
One way cost 3 EUR, therefore you might want to walk....
Don't miss to take the boat to make a trip on the Neckar river. This pic is taken in Neckarsteinach, a beautiful part of the Neckar valley.
Heidelberg is situated on the intersection of the autobahns A5 and A656.
The airport of Frankfurt is within one hour.
I recommend to use following e-map for Heidelberg.
fast, detailed, simply good!
By train (Deutsche Bahn).
The photo is a view from the First Class waiting room in Frankfurt.
It is free for Europass holders. Really a respite.
Strassenbahn, busses, bicycle, walking.