Jenks- I wish I had enough time at the moment to cycle 80 miles a week! Nuff respect.
Tea- I'd recommend getting a pack of cycling maps from ANWB/VVV- really useful for planning where you fancy going and the one we have (Landelijke Fietsroutes 1:150 000- details
here (scroll down)) is made up of lots of mini maps, which are easy and light to carry whilst on a ride.
You can do a lot of miles easily in Holland, unless you are on the coast and cycling into a headwind or near Maastricht (has hills)- you can pretty easily do an Alkmaar-Hoorn loop from any of the central cities without any practice/training. Or, cycle somewhere and get a train back (or vice versa).
The Hoge Veluwe National Park is great for cycling