Chas: Yellowstone provides unlimited creative photographic opportunity. Unique landscapes found nowhere else on the planet and abundant wildlife in daily struggle for survival. You never know what will unfold on a day to day basis.
I typically take multiple Canon EOS R5 and EOS R5C bodies, compatible batteries, cages, accessories, and the similar ergonomics of these cameras is a major plus. My lens selection includes a Canon RF600mm F/4, RF100-500mm, RF 24-105mm, RF-10-20mm, and an RF Extender 1.4X.
Nathan: I use an EOS R5 C with a super-telephoto prime and a flexible lens telephoto zoom lens, like the Canon RF 100-500mm f/4.5-7.1 L IS USM lens. I always have my Sachter tripod and monitor with me, and I’ll typically shoot with V-mount power to help run my camera and monitor all day.