I did it a few years ago after I got done deer hunting in Igaho a couple years ago. Guns are fine as long as they are in a case out of reach, and preferably locked. With meat and antler you MUST stop at the entrance and declare it. They will take your info and write it down. If you have meat/antlers you MUST proceed directly through the park WITHOUT stopping, and then check in with the rangers where you exit, as they track people with meat/antlers. Hope this helps.