Maybe it’s not so far fetched to think CW could have originally planned to drive somewhere earlier in the night, had she arrived on time. Do we know for sure that CW was aware of neighbor’s cameras? If he wasn’t, he might have thought his neighbors wouldn’t necessarily find it suspicious if he left the house around midnight. Seemed like a quiet neighborhood, and I’d imagine it’d be even more quiet at night, in the dark, with many asleep.
I’m starting to think it wasn’t originally planned to hide SW’s body at the oil tank site. The girls, yes, but I don’t know about the burial being planned. Had SW arrived in time, I wonder if he pre-planned a spot to hide her body, or some way to dispose her body, under the expectation that she would be arriving home around a certain time (e.g., around 10 or 11pm).
That might better explain what he was doing between 2 and 5am. I believe SW was killed pretty quickly, sometime between 2am-4am. Maybe it's as simple as CW spending an hour or two researching a back-up plan on Google due to her late arrival. Those internet search histories will be enlightening. Jmo