I don't see the point in playing 'Whack A Mole' with the vaccine.
By the time you vaccinate a high risk area and have the 2-3 weeks until the vaccine actually becomes effective from the first dose, the virus has either been stopped or spread exponentially already.
May as well just keep on the current track of vaccination via age nationally or, if they really want to pinpoint it, give it to inner cities/where population density is highest.