If you are going out of town for a week or so, Spray a whole can of WD-40 down the carb and into the spark plug holes until you get back. Then pull all the plugs and work the engine over by hand (or breaker bar) until you can turn it completely over several revolutions. If you can't turn it over, with the plugs out, by hand or with a breaker bar fairly easy, you may have to do some tear down.
Change the oil before you start cranking on it with the starter. Put a battery in and crank it over (with the plugs out) for 10 seconds or so (several times). File the points and clean or replace the plugs (check the gap on the plugs and points. Make sure you have a clean gas tank, or get your gas from an external gas source. Prime the carb with some starter fluid and try to start it first before spending too much money on it. If it starts or runs, then start with plugs points, rotor cap, carb overhaul, etc.
Check the valve adjustments and make sure you flush the coolant. Watch the water pump for leaking. replace any dried and cracked hoses or belts.
