Might want to not spout off about things you don't know.
Hell Corvettes, Trans Ams, and GTO's can all get high 20's and even 30MPG on the highway.
Just because it has a V8 doesn't mean it's a gas hog. When cruising, they don't use that much gas, It's when you put your foot to the floor that they start drinking the gas.
OP should as other advised in the other thread buy a less expensive economical commuter car and buy an older Chevy or Ford truck for his truck duties.
Though driving a truck is sooooo much more comfortable than being in a little econobox. It's roomy, they absorb bumps better, you have better visability and if you get a 2 door you don't have to worry about friends asking for rides.