Public roads cost money, and those costs are offset in part by plate fees (at the state level). If you have a huge plot of land and your own trails or roads, I'm sure you can drive around on them without plates.
Certainly, different states charge different amounts for plates and the privilege of using the roads. Being a state level fee, it is something that local groups can work to influence. For example, California is outrageous (think $400-$800 plate fees per year) while other states like Michigan are more reasonable.
I am a Ron Paul Republican.
The Philosophy of Liberty