Simply place a vehicle and you will enter automatically. Optionally pick the vehicle back up when you exit.

Currently the mod does not automatically insert fuel and ammo. My mod Ammo Loader+ is a great option if you want this functionality.

If using the pickup option, fuel and ammo will be returned to the player's inventory (as if you mined the vehicle).

An update of Just Go! by Folk to 0.17 until he updates it himself.