We actually did most of your proposed route, only the opposite way. We were coming from the south out of Switzerland into Germany, and intersected the Rhine Route at Waldshut, Germany near the Swiss Border. We diverted from the Rhine Route in Germany just east of Nijmegen, The Netherlands, making a loop into Belgium before riding another loop to Amsterdam.

If time is critical, I'd suggest spending more time from to the "Middle Rhine to Switzerland, than the more industrialized sections of the route from Rotterdam to the middle Rhine. That is one of the reasons we took the Route through Nijmegen instead of following the river into Rotterdam.

There are a couple of nice and relatively inexpensive hotels (Ibis?) on the bike path 2-3 miles from the Schipol Airport. If you want to visit Amsterdam, the train station is located under the airport. The hotel has a free shuttle to the airport. It is a short train ride into Amsterdam.That saves trying to keep your bike and gear safe in a city notorious for bike theft. Then you can just ride from the hotel to the Airport in 10-15 minutes. Schipol Airport has great bike boxes, and a quiet place to do the packing. However, with a hard case this is not an issue for you.

We were in that part of Europe from the first of August to mid-September. We had a lot of wet days I would also suggest touring after the wedding rather than before. That schedule takes some of the pressure off having to "get there." The worst case scenario in is missing a flight or being late getting back to work. Better than missing a friend's wedding!

A good source of information about high quality campgrounds:
http://www.eurocampings.co.uk/en/europe/

Most regional trains, while slower, do take bikes.