Welp, time to make bad decisions. She'll travel up that river, though when she hits forest she'll have to go a lot slower due to her prosthetic-- she can't feel when it's tangled on something in the brush, so she takes extra caution not to fall on her face. (I'd say it would make her at least a third slower than normal, but it's up to you, really.)

She'll keep going until she either finds a way to ford the river, finds signs of human habitation, or has to stop for nightfall.