You're absolutely right to be cautious. Just to get the engine going alone you'll want to do it by hand - and before you do that you'll need to take the spark plugs out and lubricate the cylinder bores. Too much friction at this point and you'll snap the piston rings. If it's stuck solid, try filling the bores with a cleaning solution (or a cola-based fizzy drink) and leave it overnight before applying more oil and trying again. If it does turn over easily by hand (ie with a socket on the crankshaft) then you can replace the fluid and filters and try to turn it over with fresh fuel and a battery. If you do decide to bring it fully back to life, you'll have to clean/replace the fuel lines, check the fuel tank isn't corroded, make sure all the electrics work such as the fuel pump, and get the brakes going again. If it's immaculate, it's a project well worth embarking on.