It is kind of a PITA, I had to go to DMV 4 times until they finally got it right. Some how they have to "trick the computer" into thinking your registering a quad or something so that it'll let it go through becuase there is no classification for "offroad vehicle only" you'll also have a dual registered vehicle. Remember to specify that no tires will be touching the pavement at any time during operation or towing of the vehicle, if you dont then they wont let you get the sticker... not a single tire can touch the ground.. very strict!
That reminds me... I need to get another green sticker because mine went with the half of the frame that was cut off.
Good thing is... once you get it tagged then its only like $20 every 2 years and no smog...