Day/Night Cycle Part 2

So, Darcy, wouldn't this scenario require at least 3 versions of the valley with the necessity of stopping and potentially interrupting the rising tension--day, stop, load dusk, stop, load night--because there's no possibility of just having the ambient lighting fade?
But why would we set up an encounter that specifically confounds features we don't have? That doesn't apply just to a day/night cycle... there's always going to be adjustments that will need to be made to a plot's implementation with regards to what you have to work with.

To wit, there simply hasn't been a situation yet that we haven't been able to work around, design-wise. We obviously cannot, however, predicate an entire plot on the possibility of un-triggered transition into night... but the question then would be: do you really need to set it up like that?