Mearrin69,
Most of my suggestions are in the fantasy area, but some classic settings you could map: underground sewer system with lairs and dungeons, flying citadel/castle, ruined sunken stone city, city block (showing all the rooms on the ground level--I think something like this was done for Harn), temple or shrine, bandit caves, lair carved into a huge tree (perfect for a druid or fey), abandoned (or maybe not) pyramid, clock tower and/or engine room with lots of gears. Curious to see how your series turns out. Good luck.