I think you should be OK. Like other's have already said, just turn on your flashers and have a car follow behind you with it's hazard lights on. If your in doubt, check the law. I know in MO that it's perfectly legal to drive a tractor on the road provided that its for agricultural purposes and you obey all traffic laws.
Here's my tractor road driving experience:
Just this last winter, our farmers were just finished up combining the corn in the fields and were unloading the combine into the grain bin hauler that was hooked up to the big 70's International tractor they just recently got. I was shooting the breeze and what-not with Aaron (one of the farmers) about the International (don't remember the model, but he said when they dynoed it in their shop, it was 148.3 HP!).
So, the combine finished unloading and Aaron says to me with a grin, "Want to haul the corn on up back to our place?" Well gee, it took me all of about .0003 of second to say, "YEAH!" So Aaron rode with me (supervising) with me driving. It was sundown, so I turned on the tractor lights, flashers, and the other farmer followed behind us in the truck with it's hazards on.
WOW - what a difference there is from a CUT/50 HP or less tractor to a 145 HP agricultural tractor! The cd player in the cab, with heat was pretty nice and the ride was a lot smoother then I thought it was going to be... I couldn't believe how easy it was doing 15-20 MPH down the highway hauling a loaded grain bin. It was a blast! /forums/images/graemlins/grin.gif