As a minimum, I would change the oil and filter, and drain out any old gas left in the tank. Change the fluid in the cooling system.
You might try removing all the plugs and rotate the engine with the starter and see if the oil pressure will come up. This will tell you if the oil pump is working, and will also get oil to the bearings, lifters and hopefully the rocker arms. If no pressure, undo the line to the gauge and rotate again to see if in fact you do have pressure and a bad gauge.
Next I would do a compression check, just to make sure you don't have a stuck valve. You could remove the valve cover and bump each rocker with a mallet and make sure everything moves like it should.
If it starts, keep an eye on the oil pressure and the temperature. Listen for odd sounds. If it knocks, shut it down.
Kurt
