Trenton, I have used a tenzing pack for a couple years now, it has plenty of room for most all of my hunting gear when I'm hunting Nebraska. I have another bigger pack that I use when carrying meat out. That being said I just bought an Alps pack and frame for when I go back to Colorado, found it on Camofire, and at a very reasonable price. Something to think about, since you can't bring any bone back to Michigan, get a cheap tarp, we use it to lay quarters on and debone them. Get some 2 gallon zip lock bags to put meat in after it's deboned. As for boots, since I hunt in December out there, I have been in blizzard conditions to 60-70 degree temps, so I usually have a couple pair of them, I take my Muck boots and have a pair of Danner Pronghorn that I take so I can be ready for any weather, since you'll be there in September a good pair of light weight boots would be ok. If you're going to be hunting the prairie or sandhills, be careful if you are trying any stalking, you'll want to watch out for cactus, they grow flat on the ground, not any fun if you sit on or crawl over one. (I've never done that but have come close a few times!!!) Hope this helps answer some of your questions. Good luck when you go.
Jason