Welcome to Huntchat!
First off, I've never hunted the Teton Range, but I have hunted some places that probably offer terrian very close to that area.
Being your first hunt out there and from PA (much like myself), there's practically nothing around our area that can prepare you for what you are about to partake! You'll probably never want to leave.
If you haven't been hiking and walking daily, it may be a little late..but I'd get started. Walk the steepest hill you can find and then do it again and again. After about 50 times, you feel like it will of one day of hunting in the Mountains!
No really, just take your time climbing, getting up into elevations of 9,000 and above you'll definitly feel the difference in the "lack" of air.
As for the area your hunting? Well I've been through there many of times during Sept/October and seeing about a 1000 - 2000 head of elk in the wintering range around Jackson Hole really will get your blood boiling. There's plenty of elk in that area for sure....at least the last time I was there, I saw a lot.
I know we have some Jackson Hole, WY members on the board so maybe they can better help you with the area. In any rate, Good luck!