During the Clone Wars many of the vehicles acted on their own and did not require a pilot. Many of them used by the Confederacy. I've added the following lines to the "cis_tread_snailtank" under MapScale and WEAPONSECTION = 1
Look at this video. Near the end the two Droid Enforcers on the left move on their own. The one on the far right does not have any time to move before the game ultimately crashes.
If you want the whole vehicle to pilot itself I don't think you put the "PilotType = self" line under any weaponsection, just under properties near the top of the odf.
Just a note, it's my understanding that having Hover self piloted vehicles immediately crash the game. At least that's what has happened to me, and several other people. Maybe we're all just doing it wrong.