I have done guided elk hunts in Montana for over 20 years. My hunting buddies and I have pondered doing a DIY, but we concluded we might die doing it. Having access to horses, pack mules, tent camps, cabins, etc are a big deal in the big, big country out west.
Weather is a critical factor on elk hunting. The wind is especially critical in stalking elk. I've been glassing a herd of elk several hundred yards away and if they wind you, they're gone.
DIY elk hunt is quite a challenge. Randy Newberg does a lot of excellent videos on elk hunting.
A 338 WM has been my go to elk rifle for several years. A 225 gr Swift A-Frame is what I load. Get in really good shape as the altitude and steep terrain is tough.