Hi there Rambledmind, welcome to the Guild! Well I'm not one of the river police (so I might be wrong), but I think the mountain and river placement look pretty good (though I'm not sure if the long river in the North-Eastern continent would realistically survive the heat of that large of a desert). Is there some sort of story behind the lava lake (I assume that's what it is) in the small central continent?

Cheers,
-Arsheesh