@cgmills Thanks for reaching out!
Great question, thanks for asking! The Keen Durand II will be sized very similarly to the Targhee III. You should be good to go with the same size. You will want to bear in mind that the overall feel will be different because of the differences in construction (i.e. boot vs shoe). We recommend checking out the Expert Advice article How to Lace Hiking boots for some tips on how to make some adjustments to your boot if needed.
Hope this helps!