Many rural folks have a junker or two around. If not, there is usually a local salvage yard. Pack the ramps with junkers and and light 'em up or pull the wheels off. (burned out cars make lousy shelter and may act as a deterrent).
Put up a big sign that says "Epidemic in town no doctor". At least you might get someone with a useful skill, and most others would be deterred.
Small towns will have to band together.
They’d never make it this far in a vehicle. The Pike would be blocked by wrecks and bodies before they got 10 miles from Boston. If they got as far as my place, it would be on foot, unarmed, and dropping from thirst.