I Know I'm on an ACA blog -
But I really cannot understand why they suggest a north to south direction -
Especially since they are in Missoula, Montana.
Maybe when they developed it in the late 1990s and early 2000s there were low-snow years.
But moderate to heavy snow years make the northern sections tough to use until July.
I've lived in Wyoming for 20 years and have hiked/biked the high country a lot.
July may seem crazy to people unfamiliar with the Northern Rockies -
But if you hike in the national forests, you know to expect snow banks.
Think about it -
You can easily get 10 to 20 feet of snow over the winter.
You definitely get snow into May - although snow melt starts in April.
Short June snow events are not unusual, either.
Even if the snow is gone - the dirt roads are often mudholes.
All of that moisture has to go somewhere.
Here's a link to last year's opening of Glacier National Park's Going to the Sun Road.
It can be used as a proxy for how long it takes to clear out the winter's snow.
And remember, GTTS is plowed - most forest roads simply melt out.http://missoulian.com/news/state-and-regional/article_791a1b26-7f48-11df-b37a-001cc4c002e0.html
Then there's the precipitation patterns.
As I stated before - May/June is the peak precipitation period in the Northern Rockies / High Plains.
May places see half of their annual rainfall in those two months.
By contrast, July/August is the peak precip period for New Mexico - again, maybe half.
When you are riding dirt roads, it generally is a good idea to plan for less rather than more precip.http://www.wrcc.dri.edu/pcpn/west.frac.aprmayjun.gifhttp://www.wrcc.dri.edu/pcpn/west.frac.julaug.gif
I've ridden most of the Canadian section.
I really don't see how you will be able to get over Elk Pass. (on the border of AB / BC)
You can follow the Paved route from Peter Lougheed to Highwood Junction
And then take the Forestry Trunk Road (dirt) to Hwy 3.
It generally follows the Livingstone and Oldman Rivers and is lovely.
Highwood Pass - on pavement - may still be closed.
The store at Highwood Jct may not yet be open.
Another store is at the Hwy 22 Jct.