Make your own mesitylene by trimeric condensation of acetone, then react with aluminium chloride to rearrange the methyl groups, distilling out xylene, toluene and benzene. Acetone can be made from reacting chalk or limestone, and vinegar and dry distilling the resulting calcium acetate.
"In the laboratory, it [mesitylene] can be prepared by trimerization of propyne, also requiring an acid catalyst, affords a mixture of 1,3,5- and 1,2,4-trimethylbenzenes." (wikipedia) Propyne is also known as methyl acetylene, which is a component of MAPP gas, used in high temperature blowtorches (a time-saving device for plumbers?!)
There should be tons of limonene around in California. They do grow oranges there, right?
Steam distillation of orange peel is also fun, but you might need a large setup to make enough to be of much use.
“There is a way of manipulating matter and energy so as to produce what modern scientists call 'a field of force'. The field acts on the observer and puts him in a privileged position vis-à-vis the universe. From this position he has access to the realities which are ordinarily hidden from us by time and space, matter and energy. This is what we call the Great Work."
― Jacques Bergier, quoting Fulcanelli