Be very patient- - - - -don't get in a hurry to hear it run. Start by pulling the spark plugs and soaking the cylinders with a lightweight oil like PB Blaster, Marvel Mystery Oil, or KROIL. You might also pull the valve covers and soak the valve rocker arms and guides with the same penetrating oil. After a week or so, try turning the engine by hand, maybe with a medium-length pry bar on the flywheel teeth. Don't force anything. If it's reluctant to turn, find out why. Anytime an engine stops, a few valves will be partially open and air (and humidity) can move in and out due to temperature changes. Those cylinders will be subject to rusting.

Try using a USB camera borescope and a laptop computer to look at the condition of the cylinders by putting the scope into the spark plug holes. I use the same 5MM camera for inspecting cylinders that I use for inspecting rifle bores- - - -clear down to .22 caliber size. If there's no serious rust, and the crankshaft can be turned through at least two full turns without locking up or getting hard to turn, you probably won't need to do any major disassembly. There's a very informative tutorial in the "tech tips" section of the forum about "waking up a sleeping engine". Read it- - - -twice- - - -before proceeding any further. It will be time well spent! Good luck!
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!