I don't know why everyone says after 1776. Yes the king sucked but prior to the Revolution most people in America did their own thing. I think that Colonial Americans were way freer than we are.
If I had to peg down the most freedom it would be before the Civil War. Certainly NOT after 1913. Before 1913 and the Great Depression the government was almost entirely out of the economy. Before the Civil War even more so, because Big Railroad and Big Oil weren't really in bed with government either. Income tax also came along in 1913. So as a whole I'd say America was the freest from 1600s - 1860s.
If I had to choose a small window of ultimate freedom, however, it would be out West before the federal government was there. If I could choose to live anywhere at anytime I would chose to settle the
West. Settling the West would be Heaven on Earth for me.