I think its pretty clear that the Kidneys are the root problem here.
Classically, Chinese doctors used very few needles, 1, 2, sometimes 3 needles in a treatment, because acupuncture uses the patient's energy to work. Your patient is very clearly a deficient person, which is all the more reason to try to save her qi. Her negative reaction after your first treatment is to be expected because with the number of needles used, she was drained further. If you continue with needles, I would recommend picking 1, Kd3 (not bilateral).
I would only do moxa on this person. Indirect stick, 5-10 minutes on each point. As for point selection, keep it all below the knees and keep the heat level mild and you will not have to worry about any side effects from the heat. If you were to pick points on the torso, I would be absolutely sure that her blood pressure is ok and that she could tolerate the heat.
General points to strengthen: St36, GB39
Help circulation in the legs and feet: Lv5, Kd7 - this is a classical moxa prescription used for poor circulation in the low extremities due to deficiency. I use this very frequently on patients going through chemo, and diabetics.
Build Yin and Blood, strengthen Kidney: Kd2 - textbooks say this point is for reducing fire. But, indirect moxa here clears deficient heat by building Kidney Yin and blood.
As for putting these points together for treatments, when her foot pain is severe, I would do Lv5, Kd7 bilaterally, then moxa 1 Kd2. If her foot pain isn't so bad, I would do St36/GB39 bilateral with 1 Kd2.
Finally, at the end, I would always put some burn cream (Ching Wan Hung) on the points just to protect the skin.