U-S- Highway 1954 - 1954 was released on:

USA: 2 August 1954

A state highway is a road that is either numbered by its state with a number that is lower than U. S. national highway routes, or a road that is a U. S. national highway route, but is maintained by the state in which it is located.

66 British pounds = 130.5348 U.S. dollars.

Disneyland - 1954 Magic Highway U-S-A- 4-26 was released on:

USA: 14 May 1958

Not sure what you mean, but U.S. Highway 66 has always had that designation, literally from the day it opened.

U.S. Highway 666 was re-numbered as Highway 491 in 2003.