The last half-dozen years have seen an explosion of interest in the cosmology of novel string compactifications, since it is now possible to see how cosmology fits into a fundamental theory. I will argue that understanding these compactifications more carefully is important to describing cosmology in them. I will report very briefly on progress on two cosmological issues related to dimensional reduction. First, I will present evidence that, despite a complicated process, the dimensional reduction leads to small changes in the naive 4d theory. As an adjunct, I will present a time-dependent solution of the 10d theory that might lead to a better understanding of higher-dimension effects in cosmology. Second, some Kaluza-Klein states with almost-conserved charges have been proposed as dark matter candidates, but new information about the compactification dynamics suggests they may decay too quickly. I will give preliminary estimates of their decay rates based on new information about the dimensional reduction.