WV is a beautiful state! Wonderful areas for camping as well. Most of us have become so accustomed to electricity, a home, etc., that we forget people have survived for generations without running water, indoor plumbing, and electricity. There's no reason they shouldn't be able to survive with knowledge of being outdoors, camping, etc. A campfire would keep them warm, as well as heat water for formula, or heating bottles, cooking, etc. One media report stated he packed a tent, and sleeping bags, and other camping items. As long as the tent is waterproof, it hasn't gotten 'that' cold yet. It will be colder in the mountains at night, but again, a campfire will give enough heat. If this is how they are surviving, they'll be going to bed at dark, and probably waking up early. If it were to get too cold, they could get in the van and sleep. Likewise if starts raining, they have the protection of the van if the tent isn't waterproof. (Ours lost the waterproof protection being stored, and we didn't find out until we went camping, and dew came through the roof, and had everything wet.) While it nights are a bit chilly, having a baby with someone else in a sleeping bag should give the baby enough heat to be ok.
My concern is whether he is forcing breastfeeding, or did he purchase enough formula? While it isn't safe to do, he may even have a kerosene heater, and needed to purchase more fuel for that, or for a propane tank. If he's using the van's heater, he may have needed gas.
While the kids are in danger in a sense of what he may have done to the girl, and may be the father of the child, I don't think they are in danger of him killing them. In his mind, he probably believes he is protecting his 'family'. There's violent predators and there's family sexual abuse. While both are wrong, usually the stranger wants to kill to prevent the child from telling, whereas in this situation, if that was the case, I think it would have happened before the baby was born.
Keeping the kids in my prayers. Keeping eyes open for that van. Will be traveling this weekend, near the VA/WVA border, and visiting the Parkway. I am going to write down their names, because the other day I got to thinking, and I couldn't remember the names in case I saw the van!