Thanks, Todd.

Right now I'm trying a couple different ideas to see what (if any) difference they make.

Frozen bottles bought a day or so of leeway, even in direct sun all day. I'll remember that for the next time I take a trip.

Next week I'll be doing this with a leftover silverized sun shield laid on top of the hatch deck, to see how that affects the trunk temperature.

I'll be pulling out one of the bottles every couple of weeks to see how long it takes them to start tasting 'funky'. And checking periodically to see how the Clif Bars in my GHB are faring.