A 5 wt would have been ideal for your area. During the year I spent in Midland, South Dakota I went out to the hills every chance I got to be in the mountains and get some trout fishing in. Many wonderful lakes and small streams with decent trout fishing, which is why a 5 wt would have been ideal.
The 8/9 wt you got is a bit heavy for the streams and lakes in the hills; but you can get by with it. Unless I remember incorrectly, the SA combos have a WF floating line included in the package. If not, you should get a WF (weight forward) floating line and knotless-tapered leader of 9' long that has a 3x or 4x tippet.
I seem to recall there is a pretty nice fly shop in Rapid City. You should look them up since Rapid is not very far down the road. I assume you are going to school in Spearfish since you mentioned you were a college student.