Tip to travel for a quick trip to Paris/ Amsterdam etc from Dusseldorf

Can anybody suggest some good way of traveling for a quick trip to Amsterdam and Paris  and other cities if possible. I am coming to Dusseldorf for a business meeting and I will be free on Thursday Night. I can travel on Friday, Saturday. Any suggestions/ tips to make this trip viable and enjoyable will be appreciated. Thanks!

You can use www.bahn.de to get train tickets. I think it's the most convenient and cheap way to get to most places in Europe. From Dusseldorf to Amsterdam Central station it can be just about 19 euros if you can book well in advance and get a saving fare, which is a fixed time ticket. Normally you can buy a ticket and hop on any train going to the same destination, but if you choose a fixed one, you can get a saving (or reduced) fare, and save cost.
From Amsterdam Central Station , you can buy a train ticket to Paris. You can choose the Thalys high speed train. You can buy the tickets for that from www.thalys.com. I think on saving fare, it costs about 66 euros.