Kid,
From the Snowy Range exit on I-80, go west. Stay on 230 to Woods Landing. At Woods Landing, turn left and cross the Laramie River. Then go south a few miles on hwy 10. There are two access areas on the right. I like the southern one of the two. There is one more access farther south, but you need 4 wheel drive and a strong stomach to get to the river. Most of the fish are browns, and the water will be low and clear in September. Generic dry flies like Adams, EHC, and stimulators will work, but for September, you should have some Trico spinners. If you tie your own, about size 22 or 24 are best. Be sure to take your own, because the local shops only had 18's the last time I ran out, and 18's are more than twice as big as the naturals. The access closer to Laramie is on 230 also. It's called Monolith. Watch for the sign on the left just a few miles out of Laramie.
Good luck,

Arnie