Good color throughout the image. You have a couple of specks in the upper right of the sky. I think if you had shifted the composition a bit to the left, so the path wasn't so squeezed out by the arm, it would look better.
Good idea, and nicely done. It's a bit static with the horizon line in mid pic. There's a bit of sensor dust (at least it looks like it in the RUQ). Lowering teh gps unit to 1/3 may have helped with rasing the horizon to 2/3... just suggestions tho, on a good idea. 6
A Garmin 60CS! I have the same one, and I'm using it VERY heavily this week as I'm doing hurricane clean-up in Mississippi. Others down here are very jealous of it, since most others are having trouble finding their job sites :) Oh, cool picture, too.