Lee Thomson has a copy of Gene Roddenberry’s March 1964 pitch for Star Trek. There were many changes made before the first and second pilot episodes were filmed. For example, the ship’s doctor went by a different name, but was still known as "Bones". Sex kitten Yeoman Rand was called "Colt", and Roddenberry clearly had a larger role in mind for that character.
"STAR TREK is a "Wagon Train" concept -- built around around characters who travel to worlds "similar" to our own, and meet the action-adventure-drama which becomes our stories. Their transportation is the cruiser "S.S. Yorktown", performing a well-defined and long-range Exploration-Science-Security mission which helps create our format."
Take a peek at the original pitch document
(.pdf format), and enjoy!