Grant: some of those suggestions can be some fine areas to see. One thing of note and it's been covered by Gary and Lithos is those workshops can be teacher instead of student oriented, so I understand your concerns.
I personally (if visiting Yellowstone/Yosemite) would seriously consider seeing see the "less populated" areas, avoiding the more visited spots if the opportunity allowed. It's always that catch-22 of "do I photograph the same place many others have, or...?" Zion and the Grand Canyon would work well together, no question.
So why would anyone be embarrassed if you named someone? Sounds like you have a list...
Regards,
Marc