I'm currently adding towns and cities to the game. Each will have its own tile map and you'll get quests and clues and shops in cities and towns.
I don't have my own tile map editor yet. I've been using the imaginatively named "Tiled" tile editor. It's pretty basic but it's free and it does what it does very well.
I threw around the idea of having a single huge streaming tilemap, so everything can just be to scale, a bit along the lines of the classic "The FaeryTale Adventure" on the Amiga, but have settled on separate maps per location as in Ultima 3 and 4. If you've played WoW from the early days, you'll remember long hours of running from town to town until they eventually started adding flight paths everywhere and everyone got flying mounts. It did give you a great sense of open world, but eventually you just want to get to the action. I could put teleport gates around the place like in Diablo, but there's numerous advantages in smaller maps... It's easy to edit them and easy to redesign your main map or add new wads of content at a moments notice...
So now I'm putting in cities. I've added a bunch of them that I thought sounded interesting. Nothing set in stone. In the cities you'll be visiting shops, getting quests and clues from npc's and playing mini-games. The mini-games will be a big part of the community aspect of the game - leaderboads / challenges / etc... But more on that another time. Suffice to say they will be entirely optional, and will be quite diverse.
Ok, the kids are in bed and the wife will be off to bed soon so time for me to get some work done.