I have just been reading the latest chapters and I can see you've got a great story going here! I think I should go back and start this from the beginning!
Initially, I thought my rockets could reach that far (I was reading the wrong column, looking at the speed! o ) so DC, New York, and Boston were going to be my targets. After which I would have wrote the US out of the war. Sadly, I can only reach 1,000 miles with them. So deep into the remnants of the Soviet Union, or anywhere over the United Kingdom and Northern Ireland.
With the Russian bear pacified for two years now, I don't see why the Wehrmacht would not be able to rail a corps or two of experienced crack troops in from the east.
YES hit London and other high-value English VP's. Knock them out and you'll do fine. Do you have the Navy to at least keep the US at bay while you prepare for them?