Thanks for the insights - they will be really helpful.

Yeah my thought was that since the city was built as a trading hub it would be constructed close to the beach and people would just walk a bit further to the river for fresh water or set up farms near there. It makes sense that originally they would have just had some sort of fort that everyone could gather into during an attack. I'm thinking that later on in their development they built some sort of wall - one that roughly connects the big towers in the mountains. But as trade declined, they weren't able to keep people from pillaging materials or rebuild once it happened - so bits started to crumble...your idea about concentrating the suburbs in those areas makes a lot of sense.

I suppose the next point of business will be to establish some sort of central building/fort with concentrated neighborhoods surrounding it...and then suburbs at the points where the wall has given way.