I'd also be thinking about taking along something that can plug into the cigarette lighter bit (or USB) of whatever vehicles (assuming driving) you are using . The drivers may be happy for you to use it in an emergency, possibly all the time. At the very least, this combined with the solar power provides options and backup. Never be caught without a backup.
I'd also consider a good 18650 mod anyway, the batteries will hold their charge for a good while.
I'd also consider high mg juice. I vape less when on higher nic juices. Three draws on 24mg and I'm satisfied nowadays, for a while at least. A battery lasts for ages when you aren't vaping as much.
Now that I think about it, I would be seriously considering a bag of baccy for dire emergency.
Actually, don't listen to me, at the rate I'm going you won't have room to carry a change of undercrackers for all the vaping supplies and backups I'd be considering.