off road diesel = no no, when you place it on the road. at least here in Illinois. and if you do go on the road. and get caught you might have to pay fines. though i think there is something in IRS website to allow farmers to pay on road tax when tractor is on road. when they have off road diesel in the tractor.
double check for insurance, just like min insurance needed for a car or truck. there might be need for the tractor when on the road.
double check if you need license plate / tags. some states do, some states do not.
most require "slow moving sign" large triangle on back.
some states may require "left and right turning singles, brake / tail lights, head lights, and/or flashers.
============
it all depends per state. each DMV and there regs/codes are different for farm tractors, construction equipment, etc....