Been a while, but used to get to Kodiak regularly. Good friend ran a charter, but has moved.
I fished the Buskin River, which is almost in town and gets good runs. Also the Pasagshak River which is near the end of the road. Like most places, timing is everything. Early July there should be reds and possibly kings in the streams. There are also lots of dolly varden, which can get suprisingly big.
The best thing going will be the salt water action. Halibut fishing is great anytime. There are kings in the 30-50 pound class, more than a few. Since you will be up there I encourage you to find a reputable charter operator and get out on the salt for 1 day hali and 1 day salmon.