The ignition coil takes voltage from the battery and jumps it up high enough to arc. Then it passes that voltage across the coil wire (middle one on the distributer cap) and sends it down to the sparkplugs. If your coil's toast, it's parksville for ya. It can go in a heartbeat, with no warning at all, and the easiest way to find out is to pull a sparkplug and hold it against the head while someone else cranks the engine. That is to say, there's no easy way.
glad yer back on the road.