I'd take the decimals off of 90.00-mile-long. It's fine in the lead because you should say exactly how long the route is in the intro, but it seems like overkill here.
Done, but {{convert}} won't accept rounding the km to 2 decimal places
Does Downtown need to be capitalized in "Downtown Pullman"?
Lowercase'd
"least busiest" is the most dumbest adjective ever :p
Replaced with "least busy", per IRC discussion
History
I would split the last sentence in two, personally. The last phrase in the sentence makes it read worse than it would if it were in two sentences.
Split
Major intersections
Is WSU what it says on the signs? Or does it say Washington State University?