You've got it. Proceed cautiously, because there will always be someone to nitpick you! For example, Williamsburg was not called that in 1686, and adding 'Colony' might be helpful to non-American members. So, in 1686: Middle Plantation, Virginia Colony. Also, WT wants county names as well, but I think Williamsburg isn't in one. So, in 1945: Williamsburg, Independent City, Virginia, USA. And people will quibble about 'USA' versus 'United States' versus 'United States of America.' But just 'US' is not acceptable, I believe.
Moral of the story: Spell out the state, do the best you can with the historical name, don't let the perfect be the enemy of the good.