Found a location with magma (a volcano I think, reaches to the surface), HFS, an underground river, Iron, flux and tons of wood, within a 5x5 area. Upon embarking I discovered a 24 Z level high mountain that takes up roughly the southeast quarter of the map and decided THAT needs to become the mountainhome, and it needs the ability to vommit magma on command.
So anyway, I turned a tiny mountain into a garage for my trade depot, connected to my Mountainhome by a tunnel that I can seal off. The actual depot is on the third story, connected to the ground by ramps. I got one wave of immigrants and was trading with the second or third caravan when a kobold ambush showed up. Dorfs aparently CAN NOT path through ramps even though caravans and ARROWS can. My haulers and my broker wreseled them all to death, only loosing one unskilled dorf, with a couple of minor injuries. One of the traders got his leg shot off, however and spends 99% of his time unconcious. The caravan could not leave because he could not move and so I sealed off the trading area and walled the exit and I'm not going to open it until traps and a military is ready. I found the cave river finally, turns out its only like one screen long, running not even 10 tiles south of my central staircase. Its got Giant Olms and cave crockadiles and stuff just piling up in it, so I started building bridges and fortifications so I could start slaughtering and capturing them and stuff. Somehow a giant olm got out, by the time I realized it a hauler had gotten ripped into 14 pieces! This worried me so I drafted every single dorf and sent them all at it, but my broker/axedorf instakilled it. So cave river is off limits and I am churning out hunting dogs to escort my workers.