I indeed have, until one of my XC/softball buddies became a trainer. I didn't see anything majorly wrong with it based on what she told me (other than difficulties with getting/keeping business), but I don't really do the intentional exercise very well, especially in a gym atmosphere.

That does give me the idea of becoming a hiking guide though. No schooling required, just a good idea to volunteer (and I did apply to various state park positions yesterday).