What's your intended scale? Those mountains look great at the size shown in the thumbnail, but like jtougas says, they seem too geometrical viewed up close. One solution to that if you're willing to do a continental-size map, is to just do more of them, and smaller. I bet in clusters and strings those would make dandy ranges. That would necessitate shrinking the river width a lot though. Your forests actually would work at a smaller scale better - they're such a fine texture. Granted, if such a mountain is a kilometer or two high, it's in scale for trees to be individually indistinguishable. It's a good start !

Yeah, I wish I had a tablet too. I make do with a mouse or a touchpad, and sometimes wonder about swiping my daughter's Wacom :-).