Long distance dolly towing

The farthest I towed in one direction was 2400 miles. YES,,, check the local laws along your route.In the 90's I used a tow dolly allot towing all over the country. Got stopped in California and was fined because the car on the dolly was not registered.California Cop said if any tires of towed vehicle touches the ground said vehicle must be registered.Never had a problem in any other state(at the time).
Also U-Haul charged $900 to rent a tow dolly from LV Nevada to Pittsburgh Pa.The friend said that he could have had the car shipped for about $700.