Hallo Rood -
I used to have red hair, but it disappeared.
As you may know, the U.S. has more hills than the Netherlands - even Limburg. ;-)
You know, there is no such thing as perfect timing.
Even the best planning for weather is likely to encounter significant unexpected events.
In the Pacific Northwest in 2021 there was record heat in June.
In 2022 - when I rode - there was record cold.
As for wind, I have ridden X-USA many times.
There is, perhaps, only a small benefit from riding west to east.
There are specific areas where westerlies are strong - mostly in the West.
Besides temperatures, there are two other important factors - precipitation and fire.
The Great Plains get almost half of their precipitation in May and June.
Plus, it often comes in big storms - just ask Dorothy. (Of The Wizard of Oz)
August in the Northern Rockies and Cascades often involves significant fire risk.
In 1988, I had to do a huge detour around the Yellowstone fires.
Right now, Hwy 20 / the Northern Tier is closed in Washington state.
Geography -
The Rockies run diagonally from northwest to southeast.
The Appalachians run diagonally from southwest to northeast.
So the further north you plan to ride, the more prairie and plains you have to cross.
And, trust me, straight roads that go on for hundreds of miles with no hills or trees get old.
As for the Great American Rail Trail - - it really doesn't exist.
It's just a big promotion for the Rails to Trails organization.
Virtually nothing in Wyoming and most of Montana, the Cowboy Trail in Nebraska is sand.
And the chance of them getting a rail trail through Yellowstone is zero.
Some of the separate trails are nice, but I really wish they wouldn't do this.
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I can't imagine it taking more than 3 months to ride across the U.S. - even going kinda slow.
My last X-USA in 2016 - when I turned 60 - took just over 2 months.
I say that because getting a 90-day ESTA is easy, a 6-month visa is more difficult.
I don't know how much time you want to have visiting cities on the east and west coasts.
Also, do you want to ride from ocean shore to ocean shore? I usually do.
It does require extra planning and, always, extra time.
One of the finest rides in the East is the C&O / GAP Trails from Washington, DC to Pittsburgh.
No cars, free camping, historic sites, gorgeous scenery - hard to believe it is in the East.
But you don't want to do it much before May 15 - - too wet and muddy.
And - skipping all the way to Montana - Going to the Sun Road in Glacier National Park is the best.
Which would steer you out towards Washington state and/or Oregon.
My guess is that 1 month for the East, 1 month for the Plains, and 1 month for the West would be plenty.
Or - 1 week east coast, 3 weeks East, 3 weeks Plains, 4 weeks West, 1 week west coast + 6 days to spare.
Anyhoo -
Let me know if I can help.
You will certainly enjoy your trip.
Tot ziens - Jama