On the tailwinds comment...
When I rode from east to west back on 2002 I had 2 to 3 days of full power headwinds and 2 to 3 days of full power tailwinds. And I met a west to east cyclist early in my tour (which meant he was near the end of his tour), and his experience was the same as mine.
It's true that the jet-stream winds flow from west to east over the US - but that doesn't translate directly to wind direction at the level of a cyclist.