Aww man, I love D&D/D20 games; and that sound like an especially fun time! I'm about to start a D20 Modern campaign (adapted to fifth edition D&D rules) where my friends and I are trying to survive a zombie apocalypse. We're using our city as the map and we didn't roll for our character stats (which makes the world extremely easy for me to understand as a DM). We all made honest assessments of our own strength, charisma, etc and already set off! Some close calls so far, but we're bunkering down in our house haha.