I have been going about every year since 08. I have a friend who has a cabin in West Yellowstone.
I would only take two lenses.
The 500mm with a 1.4x
The 24x70 L II.
Take two bodies.
Tripod for the 500mm doesn't hurt, but a mono will suffice.
You may only get a hand full of oppritunities that are great shots for the 500mm.
There will be many for the 24x70.
I would leave the 100-400 and 70-200. Added weight and seldom did I ever need them, I took everything the first few years.

Binoculars. Get one of the IS versions from Canon. The IS is a must have.