130 miles up is optimum. You could use an R-17, which is called a ‘Scud B’. They’ve been making them forever, which means you can get a hold of one pretty easily.
I’m sort of shocked it hasn’t happened yet besides Syria, an EMP or grid related attack.
Again, you’ll have pockets where the grid will survive, and anyone who hasn’t connected their generators to a distribution system should be OK.
Cars being transported by ferry might survive, for example. Submarines would make it, given water is a conductor and there is so much of it. The sub itself is an almost ideal faraday cage.
Naval ships not on shore power should be OK.
The issue, initially will be fixing the leaks in the distribution system. Insulation will be ‘punctured’ in many locations.
But one over the North East is enough to send the USA into a tail spin.
There was an old saying back in the '80's: There are 3 superpowers, the Soviet Union, the United States and a Trident Submarine. The "boomer" submarines are normally real deep and unaffected by such attacks, at any given time. Enough nuc-power to neutralize any country.
The key is trucks, tractor trailers. If they can keep running in various areas, we can rebuild fast. If you have not read that book, than you will enjoy it I am sure.