OK never stop learning - some time ago LH issued the R&F on the well known print-ticket formats and shipped them by snail mail to German adresses only!
Since the introduce the 11-digits "Deutsche Bahn" (German Railway) code to replace the printed tickets there seem to be more options!
This is good to know for all visitors who want to avoid (stupid) connecting flights e.g. FRA-STR oder MUC-NUE^
However remember that arrival after 20:00 might be with limited connections!
You can save also in avoid the 10% Car Rental Airport service charge which is charged to the whole lenght of the rentals in most cases. Travel to your first destination by train, then take car from the local car rental office at normal office hours (usually 8-18)
However as foreigners you also have following options to choose from:
http://www.raileurope.com/us/shopping/pass_finder.htm
One thing I still don't understand: for us Germans it's valid from our hometown to airport (refering to the ticket/filekey) - how do they book this for foreigners? can you travel 2 days around the country wherever you like or do you need to tell the agents where is your first hotel?