As she gathers, she thinks.
She doesn't want to spend much time any further south of here. The risk of someone running into a villager is too high. If they catch her, they'll probably kill her.
The river is a really good landmark - the rocks and plants along the bank have enough variation that she isn't likely to get confused about where along it she is, even without the tubers. And she can hear it from pretty far away - noticing that she couldn't hear it was part of how she knew she needed to turn around.
What she wants, at least for now, is to explore due north from her tree and make sure she won't overshoot when heading back from the river. Exploring the area will help, but what will help more is if she can leave a trail for herself, or at least a boundary.
Once she's gathered as many sticks as she can carry in her bag (each snapped to be about the length of her arm), she pulls out the knife and starts sharpening the ends. She's not very good at it, at first, and ruins a few sticks, but she picks up the rhythm and finishes before the sun starts to rise again.
With her bundle of stakes, she sets out north from her tree. Her monster eyes let her see about thirty paces with no light - she stops every twenty-five and drives a stake into the ground until it's about halfway in, and also stops for a minute to look around and try and find something of note. Interesting bushes here, some unusual trees there, and - oh, a berry bush!