Wow, thanks for all the feedback so far! It's all been greatly appreciated.
To clarify a few points about the route and timing, I picked September because of the NOAA climate data. If I wait until October, I could be facing some very cold temperatures and possibly early snow on the route, and I consider that a lot more dangerous than the warm temperatures. Plus, it would require me to pack warmer clothing, and a warmer sleeping bag, which will add to my carrying load. This is also why I have the route starting above 5,000-feet, and the vast majority of it is close-to or above 5,000 feet until the final stretch through Eugene to Portland.
However, I have been doing daily rides here in the valley (geared-out) to prepare, and those riding conditions have all been above 100 degrees. It's tolerable until about noon, and then it's hard to stay hydrated.
As a few have noted, I have some pretty big gaps in Utah and Nevada without any places to get food or water, so I might re-route, or at least go through and mark all those locations, and make sure I am carrying extra supplies for those bits.
It seems like there are some WarmShower hosts along the route, but they are very few and far between. I really don't mind camping, I just worry that I won't be able to find good unexposed locations for much of N. AZ and Utah, and there is probably a lot of cattle land with barbed wire. I know the route across Nevada is part of one of the ACA's routes, so I hope to find some bike friendly camping opportunities there.