The simplest thing to do is to get off the boat, turn left and pedal along the coast until you see a signpost for Amsterdam. The LF1 national cycle route (part of the North Sea cycle route) runs along the coast and you could follow the signs for it (although it does not go to Amsterdam, you would have to turn right at some point such as Zaandam). If you want to plot your own route (e.g. to visit Delft, Leiden, Haarlem or other historic towns ) you can follow the "
mushrooms" or the cyclists' red or green signposts (the green routes, where avaialble, are nicer but slightly longer). Both the signposts and the "mushrooms" give directions and distances for cyclists and the "mushrooms" are numbered and shown on cycling maps. If you do buy a cycling map, don't forget the Amsterdam is in Noord Holland province and Hook in Zuid Holland.
A direct route from Hook to Amsterdam (not along the coast but through towns and therefore more difficult to follow) would be about 50 miles, the coastal route would be about 80 or so. There are campsites at most towns along the coast if you need to break your journey and depending on the time of year (spring/early summer is best) there are tulips galore in the Lisse/Noordwijk area.