Dude, always nice to see a fellow Californian.
The map is nice, just a couple of things: As you said, the rivers look off a bit, I'm not familiar with the programs though, so I'd have no idea how to fix that. The map style screwed your continent a bunch up north, but again I'm not sure how to fix that. I think the map would look way more awesome if you upped the resolution quite a bit, to really allow some detailing to be shown. Other than that, awesome map, especially considering you're still learning the programs, well done.