Just from the general overall look of the mountains and hills in the two peninsulas, I can definitely say that the river drainage systems will be trellis style. Attached is a DOC file I wrote up some time ago for a friend. It gives a general idea and discussion on river drainage systems.
RobA also gave a good link in this post.
Also, look over this topic for some good advice.
And yes, perhaps some fuzzy brush work to allow the rivers to show through. Or you could do a select on the rivers and punch out the forest. Or you could select out the rivers, copy them to a new layer, and put them above the forest. Those are just a few ideas that popped into me head.
And the map is looking good so far. Keep up the work.