Find a small manual transmission automobile, push start it.
The O/P talked about "several months" Virtually all petrol engined vehicles made in the last 20 years will have an electronic fuel injection & ignition system, which won't operate without a reasonable level of voltage. So you are going to need at least ONE battery (or several connected in parallel) holding some charge. I wouldn't like to speculate if it is possible to "bump start" a mechanically injected diesel engined vehicle, without breaking the transmission
. Many industrial diesel engines have decompressors, and can be hand swung, so look for one of these. If you're lucky it will be on a portable/mobile generator, so the next place to go will be a workshop with battery chargers. Bear in mind that heavily discharged lead acid batteries will take a long time to recover (if at all). Also note that alternators won't usually "excite" unless the warning light illuminates first (this small current passes through the rotor field circuit). So even getting an old diesel running is no guarantee of charging an on board battery.
Small petrol engines normally have self contained magnetos, and recoil starters - again there should be a portable generator somewhere. If you are REALLY lucky you might find an old petrol engined car with a dynamo - push one of these fast enough and it will fire up even with a completely flat battery! In short, I would be looking for small equipment, and ride on mowers - anything which can be hand swung, yet ideally has a battery and charging coil.