Plan on doing that ride again, but much earlier in the morning. Did the trail even out after the halfway point and then climb again? I looked at the trail in Google Earth and it looks a little flat/valley after the 5th mile or so.
The thing that saved me was coming back in the shade! Otherwise I would have been a serious heatstroke candidate.
Yeah, that was tough. Although it was cooler than I thought it'd be, it was still pretty warm. Luckily, I put ice cubes in my camelbak, so it helped a little bit. Glad you made it back safe!