Ok.. after reading the brief, I am not quit sure if there is a way to do this map in the style of my Baldimar map with a pseudo ISO perspective. Given the East to West mountain range and the requirement than the cities be located on the north side, the mountains would cover the cities unless the map were rotated to a different cardinal direction so that North is right, left, or down(best). While most people think of things in up=north, there are a number of maps here that buck that convention, so it's not unprecedented.

The other options are to go with more of a semi-realisticy top down satellite view(like this and this) OR with a top down line drawing (such as this or the third map down on this page or this and yes, there is a reason two of those maps with this style are from our own Torstan...)

While I can do the former, it has been a number of years since I did that style, so might take a while of playing to figure out. I had tried in the past to do the later style, but did not work out to my satisfaction at the time, but would be willing to give it somewhat of a go again... Also note that on the latter two maps, the mountains are at a much lower scale and thus any I would make (in either style) would be much more representative than actual scale based.

Please advise as to the course of action...