New battery... Remove the spark plugs. Squirt some SAE 30 (engine oil) in the park plug holes (just a little). Drain the oil and replace the filter. Replace the air cleaner element. Put new pugs in it. Drain the fuel tank. Puyt about a gallon of premium gas (fresh stuff) in there, along with a can of "tank dry" or similar product. A can of SeaFoam Fuel Injector cleaner can't hurt...
Assure the tranmsission still has fluid in it (no need to change it YET).
Drain the coolant. Refill with straight water. Flush it a bit, refill with water. Put in a new thermostat.
With the spark plugs still out, crank the engine until oil pressure "registers" on the guage (or the light goes out). Install the plugs and fire it up. Allow it to come up to operating temperature, watching carefully all the while, for leaks or other obvious problems.
Hoses and all other rubber parts should be checked as well.
Good luck!
Jim