Welcome! Sounds like a fun tour.

You're not asking for routing or destination suggestions, so I'm trying to refrain. I'll say only that IMHO (emphasis on "humble") there are better routes as well as better destinations for parts of your planned trip. Of course that all depends on what kind of riding you like to do and the sorts of places you'd like to see, and of course opinions are infinitely varied. If interested in this sort of input, ask away.

Most people would not book all their lodging in advance for a trip of this magnitude, because most find adjustments necessary along the way. If that's what you're doing, be sure to make everything cancelable without penalty, and be sure to track it well--each adjustment requires other adjustments, and that can require a lot of time and energy. I travel quite a bit in the US and Canada, and seldom reserve anything more than a day or two in advance--while this might not work for you, there's probably a happy medium.

Note that some places, like Yosemite Valley, really do require reserving long in advance. Entry to the Valley will be by reservation only on many days, even if you're not staying there. I'm not clear whether this applies to the rest of the park--for example, the Tioga Road from the Death Valley (east) side to the Valley (west) side. Arches National Park, which is not to be missed if you're in the neighborhood, has a different reservation system for its one point of entry.

Hope that's helpful.

Mark