Post-apocalypse vampire roleplay

This is an old rp I used to do with a friend of mine and I'd like to ressurect it. It was a very interesting roleplay.
The world has been reduced to being post-apocalyptic due to vampires rising up and taking over the world.
A mysterious vampire king kept away from the sights of any human resistance leads the vampires in their campaign for world domination, vowing to crush the remainder of human resistance and force the humans to submit to their will.

Thirty two year old Ezekiel Blake A.K.A Zeke leads the main branch of the human resistance in Washington D.C with his eighteen year old younger sister Marina.
What Zeke and Marina do not know is that their location has been leaked by an unknown traitor... God help them all...

I am keeping this pretty low key so that myself and whomever I do this roleplay with will be able to tweak it and add whatever we like as we see fit.

Sound very fuun. How did you and your friend normally go about it?