Thanks for the advice guys. I have about a month to do the entire trip and I will be taking off from Oregon at the end of September and touring through October. From what I can tell from the maps I've looked at so far, it seems like the Lewis and Clark route follows the Amtrak train route relatively close so there is that option to bail from the tour if for some reason the weather turns for the worst.

I've been doing research on average temps and whatnot for different points along the tour route and the averages don't seem to be too bad. I think if I pack some cold gear for those just in case moments I should hopefully be alright, and if it turns for the worst just hop on the train and take that home.