The style is nice. Very true to old maps, with the rounded summits and the shade lines.

The top line is noticeably pixelated... the rest of the lines are too but there it just makes it seem like roughed and fading pen strokes. If you can I would suggest re-scanning at a higher resolution, use greyscale instead of black&white/bitmap/threshold or whatever you did, and saving the brushes as large as you can.

There is also a large difference in line thickness between your mountains and the rest of the map (for that particular background texture, I'd change the coastlines to match the mountains). If you're going for a hand-drawn look, well, line weight is a consideration... I often use one pen for an entire map, though such consistency is more a matter of taste than necessity. To each, his own.