Given the fast charging battery technology is 416 km in 10 minutes that might be a good assumption to plan infrastructure. Go for the highest economic benefit first. Take locations that spend the most on gasoline. Take one half the saving per year for 15 years. That is the fee households pay for the infrastructure. After 15 years the fee is reduced to maintenance cost. As time moves on the infrastructure cost will decease so more communities can be added. At least that one way to build out EV infrastructure.