First and foremost, well done on the video man! I really like the local flavor that your video has. I can tell you really enjoy riding. Your enthusiasm is very contagious!
It's a little tough to tell whether it's YouTube that's making the video look fuzzy due to compression or if it's your GL2. Judging on the fact that there are a lot of compression artifacts in your GoPro footage, I'd say the culprit is likely YouTube. However, you would know best since you're able to edit the original footage without the additional compression that YouTube places on the video. Could you possibly upload a screen shot of what you're talking about as a PNG or a TIFF so that we can see what your footage looks like without the YouTube compression? That would help to diagnose the issue!
Also, if I were you, I'd keep bringing up the sharpness of the video in order to help elements in your video stand out better and keep lowering your gain. The more gain you have on your camera, the more grainy it will look (which I'm sure you know).
Wish I could be of more help!