Yellowstone Park

If you intend to fish waters off the main park highways, expect big time delays because of hoards of tourists. Traffic lines at the west entrance extend for a half mile back west by mid morning. You can hear accents from all languages on the globe. The same is happening at other entrances. So get there early enough to be about the first in line. When you finally arrive at your fishing destination terrestrial insect patterns (including spruce moths around forested areas) are working as good as anything. Present these patterns with long, drag-free floats.
Fly Patterns to use:
Bionic Ant 2.0 Brown
CDC Biot Rusty Spinner
Pheasant Tail Flashback