Zim,
Vehicles and generators would be disabled. They will be able to farm what they can with their shovels and what they can water, if they don't need an electric pump, as long as their ammo holds out. No travel. No grid. No electronic communications. No ice. Have you seen grocery stores clear out in a day or two when a hurricane's coming? The food would be gone in an emp moment.
I'd say buy a horse, but someone would want to eat it.
North Korea has made test runs on our coast with a missile on board, hidden in the hold.