Can I park the automatic transmission vehicle while in neutral for a long time?

Do you have issue turning the key while it is in Park or an issue with getting the car to start in Park? Either problem is likely an adjustment issue, or a defective neutral safety switch. The neutral safety switch prevent the engine from turning over in any position except in Park or neutral. The issues with leaving it in neutral are you can't remove the keys, so the vehicle can't be secured. There is a potential for the vehicle to roll if the park brake isn't set and is properly adjusted. The ignition will also be in the "on" position potentially running down the battery.