Good morning!
Yes, that is exactly what I am saying. It makes it so much easier and less complex. It also takes away a lot of movements that would have to be done, imo.
We have to remember that murderers are already high risk takers in the first place. They do take risks and chances that no law abiding citizen would ever think of doing.
I still say he knows those properties around GW in that particular area like the back of his hand. I also think he did all of the decapitation and disposal in the dead of night. Darkness was his cover and he knew everyone's habits who lived in that area and knew they were sleeping and that all the lights around the Dermonds were off. IMO
I am not sure if it was an after thought or not. I do think after he had murdered them both he may have sat there quite awhile thinking about what he needed to do and how and why. Even plans of murderers never go exactly as they planned it. They change their plans according to what they see is as an necessity to avoid detection. Or they think of something new and add that to the original plan.
IMO