(OP). . . I'm considering purchasing a fuel tank (1000 gallon) and storing gasoline here on the farm. . . . not a big cost overall.
Others have commented on the cost/benefit ratio with opinions on the formulations of vintage vs "modern" gasoline, shelf life, etc, etc. Another consideration is permitting and insurance.
Mass. General Laws, Chapter 148, section 23 states: ". . .and no volatile inflammable fluid in quantity exceeding one gallon contained in an approved safety can, and no non-volatile inflammable fluid in quantity exceeding thirty gallons, shall be kept, used or stored, except in the tank of an automobile, motor boat or stationary engine, within fifty feet of any building used for habitation, unless a permit has first been obtained therefor from the head of the fire department under such terms and conditions as he may prescribe . . ."
There are other thresholds, I think somewhere between 100 and 200 gallons, that require annual fees and inspections. (Your Jurisdiction May Vary,)
The insurance angle is to get the permit, photocopy it, and store the original and copy in two separate places not likely to be burned in the same conflagration to prevent your insurance company from denying a claim because you were illegally storing the gasoline, diesel, or whatever.