This is a pretty old thread, they may not be looking anymore for this information, but then again who knows? I got some Nieuwendijk's here and there, seems to be a pretty common name around Utrecht. The closest Nieuwendijk ancestor on my tree I guess is Gerrigje van Nieuwendijk (1851-1932) married to Petrus Baars of Willeskop. (brother of my great grandfather) If you are looking for information on Kuiper's (or anyone) who lived around Amersfoort, try this link:

http://www.gensdvf.nl/