Apart from the language, there's not a lot different to MH'ing in Germany. The Germans are friendly and helpful, and where they can, they will happily communicate with you in English, should you ask politely. The country is clean and things are run and organised with the usual German efficiency.
There are Aldi and Lidl supermarkets everywhere, as well as other retail outlets. You will pay a tax (deposit) on all drinks bottles and crates, which is refundable upon exchange or return.
We love Germany, and have visited a few times in Aug/Sept when there is quite a bit going on. The Rhine is interesting, but can be quite industrious in places, and noisy with railways running along each side of it.
The Mosel on the other hand is beautiful and pleasent, and quite stunning in places. Stellplatz are numerous (as Aires are in France) so you shouldn't have a problem finding one, but try to get on before 14.00hrs if you can, otherwise you may well struggle, especially at this time of year.
The germans are big on cycling, with safe cycling routes all over, so you may want to take your bikes.
Have a great time,
P.S. Have a Weissbier Dunkel for me please.