I was in White River National Forest last Sept. wish I was going back this Sept.
1-The Elk rut started a little late last Sept. I was hunting the last wk of archery. I'm not sure when the full moon is. But I'd base it on that. But of the 2 I'd go with 18-23.
2-Weather wise, be prepared for it all. The wk before I arrived it was in 80's. The wk I was there, it started in 70's, and dropped to 20's with 6" fresh snow. Its mountain hunting. It can be decent on one mountain, and snow storming on another.
3- Rut, anytime in Sept. is all I can say there. Elk can be highly effected by weather conditions during the rut.
4-Yes they'll be there. Especially with bowhunting being low impact, and the 1wk muzzlelaoder season being very limited draw. Unless your going to a area with a bunch idiots running around chasing them. You can't chase Elk! They can go places most hunters can't.
5- Definitly calling is the best, so practice up. You have to sound real. Stalking can sometimes work, but they are difficult depending on terraine.
6-A whole different type of hunting. Its a challenge also. But its addicting. In my opinion if you've ever turkey hunted its most closely related to that, but harder to do.
7- My best advice is get yourself in the best physical shape as possible. If your not used to higher elevations, your in for a treat. Walk 10yds up a hillside, and your out of breath. I was, and I was jogging several times a wk all summer. The better shape your in, the more hunting you'll be able to do. You don't want to worry about being able to handle the different climate, and air. Get working out.
Also get yourself some good hunting boots. Traction is important. Take hunting clothes for all conditions. Lite, heavy, and rain gear. Be prepared to have plenty of water on hand. I carried bottles in my pack, some use hydration bladders. Take a bottle of Aleve, and some rolaids. They help with acclimation to the higher elevations. You'll get constant headaches the first couple days. Aleve worked best for that, and if your stomach gets upset, the rolaids did wonders. Take a good camera, and even a video camera if have one. You'll have plenty of down time in middle day to film, take pics. Go out with low expectations, if you must harvest a elk to make your trip worthy to you. You could be disappointed. Expect to go out to enjoy a new kind of hunting, and a harvest is just abonus.