i have a nice hardened sharp punch, and a 8lb sledge one good hit into a fuel tank, oil pan or trans pan, and a couple 5 gallon buckets, and you are dumpin fuel goodness into your tank and be on your merry way , in no time flat,
I can see punching the fuel tank because most of them have anti-siphon devices in them.
A lot of them are plastic and can be opened easily with a cordless drill with a big bit. Put your catch pan under the tank, drill a hole and get gas (assuming the owner kept the vehicle fueled up, I never let mine get under 1/4 of a tank).
In an urban, vehicle rich environment I can also go along with punching the tranny and oil pan....out in the boonies where you might have to recover and reuse abandoned vehicles I would just open the drain plug to get to the oil. Later if you went back you could just refill the fluids (assuming you could get new fluids) and use the vehicle.
Good catch on the abandoned resturaunts with all that nice veggie oil...I had not considered that. Any place that cooked a lot of food would be a potential source of veggie.
Another thought that came to my mind is rail cars full of veggie and other flammables....Archer Daniel Midland ships whole trains of tanker cars full of veggie oil. That much oil would last a long time and could be used for other uses than fuel since it is food grade oil.
This would depend on where you found it and if you could maintain control of it.
If the grid goes down I'm not sure what would happen to the railroads.....do modern diesel engines have computer control? I know there is an elaborate ground trraffic control system for trains to keep track of them and that knocking out communications would disrupt that. There may be trains stranded out in the boonies just waiting to be scavenged.
It is amazing how tied together all these systems are. One domino falls and takes the rest with it.