If you come to the Netherlands, you will be qualified as highly-skilled migrants. In this case, you can't work where ever you want. There is a list of companies, institutions and organisations which have submitted a statement regarding the admission of highly skilled migrants. You can find it here: http://www.ind.nl/en/inbedrijf/wonenenwerken/kennismigranten...
I would recommend Utrecht as a city to live because of its central location. With in one hour you can commute to many major cities.
My understanding is that if we show up as working holiday participants, we can work wherever, but afterwards you can apply for a skilled migrant visa which is different.