There are no shops in the Mountainhomes or Forest retreats, thats what the previous poster was trying to say. You can't buy anything from Forest Retreats or mountainhomes in the current release of the game. Wait for a new version, cause as it stand you can only buy supplies in towns. Actual towns with above ground buildings and roads.
As for the map, you'll have to wait until your adventure is dead, and then just go into Legends mode and export a local map of the world. Don't worry about any of the advanced options, just a basic map will do. And then you'll have a image of your whole world in your DF directory, for easy use and navigation. It can be a bit... daunting at first depending on the size of your world, but it does help once you get the hang of it.
As for finding a Dark Fortress once your in the fortress tile, I'm afraid you really only have to options, wander aimlessly until you find it, or get a 3d visualizer program and take a picture of your surroundings, it'll show you the whole tile rather then just the little bit next to you, so you can identify some land marks and get your way to fortress. However, as near as I've been able to tell, the visulizers only work with vanilla versions, so no tile sets. You can always just copy your save file to a vanilla install if your really wanting to do that, and then take the image and go back to the pretty tile sets.