This map is exactly the same as a normal FN map in the context of how it is played. Most players do not bother with the lake as it really doers not offer any great advantage except for two reasons, and that is only if you happen to be lucky enough to start close by to it. By chopping straight to it and building a dock you  may acquire a large stockpile of  food using a small fleet of fishing boats. The other reason to use the lake is to trade using docks. There is an upside and a downside to this. The upside is once your dock is built,  you have a fast trade route that does not have to be cut but onagers through the trees as you would if you was using the traditional markets and carts.  The downside is the lake always generates into the center of the map and in relative size is not that big. Couple this with the fact that you and your allies will not be on opposite sides of the map means a very low if profits trade route. I suppose even a small amount of gold is worth something if only to get you started. The coloured markers show an approximate possition of starting bases.