I suggest that we CxxxC, then CxxC, especially around this river.
We are sitting on some major commerce/science all along the river. With our Civ traits we can really CAPITALISE on the commerce. Greeks are brilliant for this. Imagine those tobacco squares, roaded up and on a river - when we hit a Republic we will be laughing!
Therefore I suggest we place cities with a view to their full expansion in the late game. This in my mind is dictated by the landscape ie. the river.
We may also want to relocate our capital (costly I know) to the centre of that river bed. Athens will give us a poor circle of influence (corruption-wise) where it is placed presently.
I'm really in favour of centering on that river region.