Hay.
Nice map, realy like the look on your cost lines.
As for mountians and rivers. Mountians usealy form where to continential plates meets, this is also where volcanos is most common.
Another way for mountians to raise is when magma presses up on a plate sending gargantum stones and pices of the plate upworts to the serfes.
a 3rd and last way (that i know of) is where magma breaks trough and slowly starts forming a mountian of its own.
Rivers have many rules. most of them explained here by Redrobeshttp://www.cartographersguild.com/sh...he-right-place
Below is a quick show of how continential plates makes mountians.
And Welcomme...
-ZB.