As a semi-local (Duisburg is just north of Düsseldorf) I would like to inform you, that there are (almost?) no direct ICE (or even IC for that matter) services from Düsseldorf to Wuppertal - you would have to travel via Hamm(Westf.) or Köln (or use the local services). On the hotel options, there should be plenty on the higher level in Düsseldorf, but they can be rather expensive during trade fairs. There is an IBIS (but only 2*) in the Main Station (which is of course quite expensive) but there are plenty of cheaper and better hotels further out (I had some very nice stays with the "Mercure" chain, there is one in the Seestern area, which gets some rather intense Light-Rail (U74, U76, U77) service. But this would probably depend on what the "aim" of your trip down here is (if it is Wuppertal, there might be some options over there and a rather good service to (some) other parts of the whole urban area). If you have some time to spare, be sure to travel on tram 310 (Bochum-Witten) - it is quite scenic and to be replaced by a much more boring line.