Thanks once again to Oldgreymare, MargaretX & LizG for all the tips, hints & enticements! Between you, together with warm endorsement from Greatnan you have have focussed us beautifully on the Moselle & the south, along with great suggestions on where to visit - for that, many thanks. The trip is taking shape & we feel very good about heading south (well, it's hopefully going to be sunnier/warmer) and as we enjoy pottering along rivers (Loire, Dordogne) your ideas fill the bill very nicely.
We're very familiar with France - even have a French DiL & extended family there because of this, so Germany in the motorhome will be a new experience and the lack of height barriers will be welcome!
The only space I can offer LizG in the van is in the bathroom, which will be full of other bits, bobs & the fold up bike.....but if you could perch on the top maybe this would do.....?! 