Hey, new guy here. I just put 1000 miles on my new 2011 S Crew. I seriously love this truck. I'm not too worried about mpg in my trucks but I have a 45 minute commute 3-4 times a week and have been playing the MPG game with my trucks for years just for fun. So far within that 45 minutes on a very flat road with Premium fuel, @ 65 MPH I can easily get 18.5 mpg if I do what I call "sailing" basically driving with as gentle throttle inputs as I can. I just put a backflip cover on my bed and a Thule roof rack on and expected to get worse milage but actually was getting a consistent 19.8 mpg on the same drive last night. Of course I only have 1000 miles on it so we will see if that remains consistent.
In my former truck, a '08 Sierra Denali with the 6.2 I was getting 21 mpg on the same route up from 18 by simply over-inflating the tires by 5 psi, adding a K&N filter and a bed cover. They advertised the '09 Hybrid Sierra at only 22!
You can start by doing simple things like keep extra weight out of your truck, keep the exterior clean as possible (no racks, light-bars, machine guns) to reduce wind-drag, don't fill the tank all the way unless you need too (fuel is heavy) When you replace your tires look for a lighter set to reduce unsprung weight. I hear the BFGs are heavy.
I bought this truck because of what it is though and I drive it as such. Most of the time I just ignore the MPGs drop the hammer and have fun with it. If you really need to save fuel I would get a cheap commuter car and save the Raptor for the fun stuff. Commuting with it is really like using a machete to spread butter anyway.
Hope that helps