You'll have a great time. Katmai is marvelous. Be sure to head out to the valley of 10,000 smokes. Non-guests can eat in the lodge, so you might be able to plug something in then. The lodge is actually one central building and a series of small cabins, and is hilariously overpriced. The campground is great.
I had a great time kayaking in Naknek Lake, so you might check in to that.