Obviously weather varies greatly from year to year, but may 1 is pushing it for W-E. Early or mid June is better, that won't have you home for July though.

If you decide to go E-W May 1 is a good time. You probably would hit the weather better that way.

Two months is possible, but pushing it for most riders. We took 73 days and might have taken more time for side trips if we weren't limited for time. Ideally another week or maybe two would have allowed us to explore a few areas a bit more.

Aug 1 might be do-able for a W-E, but not for a E-W. I would try to allow 12 weeks and then finish when you finish without a firm deadline hanging over you. If you finish in 8 weeks great, if it takes 11 or 12 you are still OK.

BTW: Depending on where you live... I think it is nice to plan direction of travel to get air travel out of the way up front. This allows a more flexible schedule.