I like the line work on your moutains. I think you could get them to really pop if you shaded them with a little more emphasis on light source. Putting the shading on the right hand side in this case would make them stand out well.
I'm not sure about the drop shadow on the coastline.I'd like to give some suggestions, but I'd like to know what graphics software you are using first.
And I agree. The Wacom pen is a totally different experience than a mouse, and I couldn't do 90% of the stuff I do without it.