Well the port was built in recent years as a naval base against Gonifus, the Pirate Kingdom, on the Mithril Sea. It anchors a chain of forts on the savannah running east from the Mithril Sea to Maradenne's second-largest city, Maranus, located on the River Accylig, as well as south along the west coast of Maradenne. You can see the map at http://www.cartographersguild.com/al...chmentid=20871, but it's over the years since I drew the map my conception changed from having it be just another fort on the savannah to having it be a fortified port on the shore. Also the erased fort just east of it isn't gone but rather, like the port itself, has been captured by the pirates of Gonifus. (That's the fort I'd like someone to design for me too. The adventure idea involves the party liberating one or hopefully both from the pirates so that Maradenne can focus more military resources eastward to come to the aid of the oppressed Volencians east of the River Wemic in the evil State of Castor.)
So it's mostly a naval base, with barracks for sailors and soldier and homes for the officers. I'm thinking that it's mostly made of stone. Since the crater is far bigger than the naval forces originally stationed there needed, it has plenty of room for businesses that followed to help service the military forces there, and indeed some of the inner slope of the crater might be used for extensive, albeit terraced farming. You're sure right about the fuzzy, imaginative spaces!
As for population, I've always thought of Maradenne as having only two real cities, Maradenne, the capital, and Maranus, the inland port on the River Accylig. Now that I'm really thinking about this other port (notice that I've never named it), I'm thinking that before the pirates took it, it probably had a population of 5,000, mostly sailors and soldiers, which would make it, according to the 3.5 DMG, at the top end of a large town.
I think the two great stone towers guarding the entrance to the harbor might be 3 or even 4 stories high (maybe 3 stories plus a usable roof with catapults). Other buildings would mostly have 1 or 2 stories, 3 tops. A warehouse might be effectively two stories high, without actually having a second story; an inn might have two or even three stories to accommodate guest rooms upstairs.
Since it was built by half-elves who are neutral good, and Annonid (Great Humans, humans with Great Elven ancestry) who are lawful good, it would have a fairly ordered layout. That's all that comes to mind at the moment.