I'm pretty sure you only need to take the safety course if you are under 16.
Registration cost me about $60, but $22.50 of that was tax since I paid $450 for the sled. Did you just buy the sled or are you renewing the registration? It makes a difference.
I'm not sure on the ditches or windshield questions, Have a look through
HERE (warning PDF) if you get a chance. Those questions might be answered.