Zubrin's plan is indeed as simple and achievable as it sounds. I have recently proposed a similar solution to Congress, and they are still pondering it.
The cost to convert a non FFV vehicle to FFV is about $350, and can apparently be done in under an hour. My proposal is to use a combination of a switch to methanol, expanded use of human powered vehicles around cities, and increased gas mileage.
The only thing I disagree with is Zubrin's statement "We can readily convert our available fuels into an alcohol supply bountiful enough to displace a large portion of the oil we import."
My disagreement is with the "large portion of oil we import." In fact, we can eliminate all imported oil using this conversion to alcohol based fuels by utilizing under 6% of our land and converting coal to methanol. And my proposed plan can be completed in under 24 months! (And cost less than what we are currently paying to subsidize ethanol and a weeks cost of the Iraq war).
Concord Minuteman Solutions Group