AC adapters aren't an option. Rechargables would be a pain to deal with on this trip--I'm trying to coordinate six vehicles on a week long trip. I really wouldn't be able to get them all charged in time without hauling some serious sized charger(s) around. Plus the fact that I can't justify the extra cost of them when I only do something like this once a year.
Thanks for the tip though. Their akalines are just a hair more expensive than the heavy duties, but it's still a good price if shipping doesn't kill it.