So I'm in Home Depot last night getting some wood so that I can modify the opening for my door to enable me to install the storm door I purchased. I mentioned something to one of the workers about my house having 6 inch walls and he said, "Oh, there's an adapter kit for that."
I could take out the door and use the kit or let it stay the way it is, which works perfectly fine. I think I'll leave well enough alone. I'm sure that even if I had the kit I'd still have to do some work in order for the storm door to fit correctly.