As I said, I played this challenge. This is my kind of game! I like the extreme! This was pretty extreme! The map is absolutely full, no buildable space left anywhere.
I went on to play my 100 educated game. You can see the start at that challenge. First it was a mixture of trade and farming, and a small green lung, with forests in the middle of the map. But as the population grew, it became a 95%-trade community. (I did squeeze in a couple of fisher, that was all the food production at the end). Yes, OK the trading and the micromanagement of the trade, is not very funny, but there is not room for so many tradingports at a small mountain map, so it wasn't too bad.
The biggest screenshot I have is with 1474 inhabitants, that was after I took a big bunch of nomads. And I can tell you; the settlement survived! I played it another ten years or so. The food was pretty low from time to time but no one starved and as the population sank, the problems was solved. I played a little bit with nomads and the bad located hospital, I wrote about in another thread. That idea work! http://worldofbanished.com/index.php?topic=836.0
I really recommend you all to try this challenge. It is really interesting to go for the limits of a map. Many people speak a bit contemptuously about trade, but in a game like this, on the limits; it's not so easy to micromanage.