Short-term bread storage I bought all kinds of bread today (Thursday morning), pitas, whole-wheat rolls, a kind of challa-looking thing. The best before is about five days time. They're for consumption on Friday night and Saturday, so up to three days from purchase, although we'll be out camping and they'll probably be in a hot car for the drive out and in bags in the sun during the day while we're walking.

For the 24 hours or so from Thursday morning through Friday morning before the drive, is it better to put the bread in the freezer, or just let it sit on the shelf?
Personally I have had varied results when freezing bread. I have had some that came out wonderfully after a couple of months. I have also had some that after a couple of days came out very dry. Note that when freezing bread, I only freeze fresh, and in a very short amount of time after getting it home. I find that results vary depending on the type and brand of bread.

All that said about freezing, I don't think how you keep the bread for the one day period will affect anything as much as the conditions you describe after leaving home. Bread in a bag in a hot car can be bad but bread in a bag sitting in the sun can be really bad. (Even on a short trip to the market I will not place bread in my car where sunlight can hit it.)

What I would recommend is to use a cooler. When preparing to leave for your trip, line the bottom and sides with frozen ice packs and cover the ice packs with a heavy towel to keep them from direct contact with the bread. Cover the items in the cooler with a towel (a little more insulation). The idea is to keep the bread at a moderate to cool temperature.

I do this whenever I carry foods that I want to keep cool but not in contact with ice packs. It works well for bread, perishables (great for salad greens), etc. 

I also learned that a couple of layers of bubble wrap can be used in place of the towels. I can't take credit for the bubble wrap idea though. When ordering perishable items I noticed that this is how they were shipped.