Geo, the ignition switch should have nothing to do with whether the starter will turn the engine over or not. It does connect the circuit from the battery to the ignition coil so the engine won't start unless the key is in the run position, but that should not have anything to do with whether or not the stomp starter should be able to crank the engine.
Have you tried jump starting the truck? If you are sure that your starter is properly grounded and that the cable from the battery to the starter is good, it should turn over with a jump start. The battery might not have the cranking capacity to turn over the engine. You can jump it with a vehicle with a 12 volt battery. A jump start should let you know one way or the other. Any FLAPS should be able to test your battery with a load tester if you don't have one.
You might also want to be sure that the engine will turn over by hand. You don't want to force anything if something has locked up and that is what is causing the problem. Long shot, but might be worth checking.
My suggestion is to forget about the gas gauge for now and assume that it is just a red herring.
Matt
