Watercraft transporters shall not exceed a length of 65 feet when operated on any interstate highway or on any highway as designated by the Commonwealth Transportation Board. Stinger-steered watercraft transporters shall not exceed a length of 75 feet when operated on any interstate highway or on any highway designated by the Commonwealth Transportation Board. In addition, watercraft may be transported on a truck/trailer combination no more than 65 feet long when operated on any interstate highway or on any highway designated by the Commonwealth Transportation Board. Any such vehicle shall display a sign of a size and type approved by the Commissioner of Highways warning that the vehicle is an over-length vehicle. However, an additional three-foot overhang shall be allowed beyond the front and a four-foot overhang shall be allowed beyond the rear of the vehicle. Such combinations shall have reasonable access to terminals, facilities for food, fuel, repairs, and rest as designated by the Commissioner of Highways.