Suggestions for photographing in the West
You will not have crowds of people during September and October in the National Parks. In fact the last few years the numbers of people visiting National Parks have dropped because the baby boomers' children are too old to go with their parents on vacation. The major group that visits the parks are retired people. [See Los Angeles Times for an article on this subject.]
I recommend that you get the National Parks pass. It is $10 for a life time pass if you are 62 or older.
Utah In addition to Bryce, Zion, ...
Visit Cedars Breaks [no cedars, it is miss-named], Capital Reef and National Bridges in Utah. I recommend that you take the dirt road to the Valley of the Goblins [west of Green River, east of Captial Reef]. It is a state park that is worth visiting. Note that Cedars Breaks and the North Rim of the Grand Canyon can close early for the winter due to snow so watch the weather even in October.
Arizona North Rim of the Grand Canyon, Navaho Monument [bring tripod on the short walk - the dwellings are hidden from direct sunlight], Monument Valley, Petrified Forest, ...
California Yosemite, Lassen, Lake Tahoe area. ... Be sure to see the Race Track and Eureka Dunes in Death Valley.
Near Death Valley in Inyo National Forest are the Bristlecone Pines. These are the oldest living things on Earth. This is worth a visit.
Further north go through Mammoth to the Mammoth Lodge and go over the pass on state route 203 to the Devil's Postpile and Rainbow Falls. Devil's Postpile faces west and consists of very black volcanic rock. It is best to photograph the Postpile after 2 PM.
Further up the road is Mono Lake, Mono Craters and the ghost town of Bodie. Check out the California Parks website to find out how to get a photographers pass for Bodie - one Saturday a month - the pass user can arrive before sunrise and stay until after sunset. The sunrises are not great but the sunsets are spectactular - just enough clouds to make the photos great!
Joshua Tree - interesting if you have not seen a Joshua Tree by then, but not all National Parks are beautiful.
Take much more film than you think that you will need. In ten days in southern Utah I shot over 50 rolls of 36 exposure film - no snap shots or tourist stuff.
Seriously consider renting or buying a four wheel drive vehicle with high road clearance for the dirt roads. This is not to do extreme driving, but to get you to places that are too far to hike in a confortable and safe manner. [Only use established dirt roads to prevent damage to the environment. Google "Tread Lightly".]
Contact me if you want more information.
Steve