I'd look at the last week of August and later, kids are back in school and most summer tourists are back home. Weather is still nice, fewer lines, traffic and issues to deal with. In Buffalo WY consider the historic Occidential Hotel, the lobby and bar are like going back in time 100 years.

 

Another issue, and maybe a bigger is where to crash all these nights. Assuming around $200 a night give or take adds up on a 3-4 week trip. This part may be the deal breaker for me.

 

You should be able to find lodging for far less than $200 a nite, Look for the Mom & Pop motels. Camping here and there an option?

 

Yeah. Currently looking into that aspect of it. Should be able to do better than $200.

 

MY default Xcountry trip weather is the month of September. A bit cooler than July/Aug, less crowds since school is back in, statistically the month with the least amount of rain, and as a bonus it gets me away from the Giant Ragweed when it blooms in TN.