It sure is. As a starting reference, you might want to read my metawriting article on MacGuffins, because that’s where all of your work is going to rest. However, for a mundane (or conventional TF, as I call them) it takes a lot more work and a lot more creativity to get the TF to occur. There are two examples I can recommend, too, a story called Redneck Garbage Men, over on nifty.org and King Coal, by Rik (an excellent author I keep forgetting to mention, and a fellow tumblr user over at bearpipe).
On top of that, I can at least point you towards a few tropes you might want to use to help jump start your ideas. First, a lot of your mental TF, if you want mental TF, is going to have to be drug induced, usually smoking/nicotine and definitely drinking. That’s the most mundane way to get people to act dumber, slower, etc. For your physical TF’s, weight gain is easy to pull off through feeding. The hard part is going to be the cultural TF–getting the person to feel like they ought to be, and eventually that they are, a redneck.
The easiest way to do this, conventionally, is through peer pressure, or authority figures. The main character feels pressured to behave like others in order to fit in, fitting in makes them feel good, they start acting like a redneck all the time, and then it becomes natural. The bulk of the story, really, is going to be this, and deciding what sort of peer group you want to use is going to go a long way to shaping your story. Is it a guy starting a new, redneckish job, trying to fit in with his co-workers or his boss? Is a young man moving in with his estranged father out in the country? (incest bonus!) Start with this set up, and then you can incorporate everything else as you go along, and it should work out well for you.
Bracken's Corner 