Used to hunt by myself at home all the time. Some days (the best ones usually) were 18 or 20 mile walks through/around the old strip mines, farms, haul roads, etc. grouse and turkey hunting with my dog. Two sandwiches, a box of shells, my shotgun and the dog. I'd tell grandma I was going hunting over on a;slk creek, or out around a;lkj ridge and back. Not sure she knew where some of those places were, but she could have told someone where to start looking if I'd not come home around dark (got home after dark a few times).
Many times, when you're used to doing certain things, you don't give the possibilities of danger/injury a lot of thought. It's just what you do. Sometimes your habits bite you.
I wonder what she saw, or what she was looking to do that made her decide to leave her dogs behind and head into the woods by herself? A dog is about the best early warning system you can have with you.