I'm going to jump in with Mark and say 2 gal to be safe. Not knowing what sort of sprayer, etc you have it isn't easy at all to say but 1 gallon probably won't do it unless you can paint with almost no overspray. Also please keep in mind you may have wheels, front apron pieces, etc to paint also and I don't know if you're painting running boards to match or not. Plus there's a chance you might have to re-do something...a fender, door, etc. Good luck!
