I left Bardstown Kentucky on May 15th going west. You can look it up on the ACA maps and judge how long you think it would take to get there from Virginia. I felt that I could have left at least a week, maybe 2 sooner. (I averaged about 55 miles / day) I had some bad winds in Kansas, not western winds but super strong southern winds. I had no more head winds than the folks I passed going east, at least on the year I did the trip. But in my opinion there are much better reasons to go west. The east is hot and HUMID in the summer and the west is just hot, and in the mountains cool. So I would rather be out west in July that east of the Mississippi. Second and most important is the light! The best time to ride (at least for me anyway) is early morning, nice and cool and you beat most of the winds, with the sun at your back, lighting up the scenery and no glare. No matter which way you go, you'll get headwinds, but going west gives you the best light and temp. / humidity riding conditions. Anyway, just another way to look at it.
I'm making plans for the Northern tier and will most definitely be going west. Hope this helped.