Hi Steve,
And it is worth remembering that ETS will have a Gartenbahn Open Day also in May 2014. May would be a great time to go. In this region, between Stuttgart and Karlsruhe they make a big deal of 'Spargelzeit' (Asparagus time) because much of the domestic asparagus is grown around Bretten. Local restaurants/pubs have Spargel Menus and some really nice food. You might also find a Maibock which should appeal!!
Cheers

Phil