If the "make your own fuel" part of your question assumes pretty much a total breakdown in the supply chain, then growing your own crops and then distilling alcohol sounds more realistic than growing crops and then pressing your own vegetable oil.

While both alcohol and vegetable oil have multiple uses, I think the value of alcohol for other uses, like barter, will likely be higher than an equal quantity of oil. And that freshly pressed oil is going to go rancid very quickly since it isn't hydrogenated like commercially prepared oil while the alcohol can last a good long time.