To go procedural or not procedural...a common choice to make in these situations, and one I make especially often when using TG2.
Many times I start out trying to make scenes 100% procedural, and I just end up with huge, complicated networks, and really slow rendertimes. In all honesty, for your example, I would model a rough shape of the island (Blender is free!), tessellate it, then bring in the model into TG2, and apply all types of lovely displacements to it. It will give you the best and fastest results, and you get to have the shape you want. Plus it will be all contained in 1 object node and a few shading nodes...nice and simple.