Make sure you know your pincode for your credit card. Credit cards are different in Europe-- they use a Chipknip system instead of the magnetic strip like American cards. My American Mastercard and Visas are NOT accepted everywhere I go, but I can draw money out of just about every ATM and use cash.
http://en.wikipedia.org/wiki/Chipknip
Your American cell phone likely won't work here either. If you want a phone, pick up a cheap 14 euro one from Vodafone. I was able to use my American AT&T phone by getting a new SIM card, but my old Verizon phone didn't work here at all (no SIM card).
Free Camping on public and private land is not allowed here in NL a lot but farm camping (boederijcamping) is very reasonable. Last summer we found farm campsites for 8 and 9 euros per person per night. Hotwater showers and breakfast was included. Most of the barns have rec rooms so when it's raining and miserable, you can stay inside, read, play games etc.
-Rona in NL