I had to do a little research to find answers to my two basic questions above in discussing this article. It seems that part of what makes it easier for women to recover post orgasm and move on to another one (if she is inclined to do so) is because her head is still in the mood. If her mind is still turned on then her body is as well.
As to my second question, I believe we would have to study dopamine, neurons, synapses, and delve deep into neuroscience to figure out why men and women differ in the refractory period. Or, more to my point, why women don't have much of one at all.