Seems like no reason to go into house or garage. We are pretty sure she was brought there deceased. This would be out of the heat of the moment, giving suspect plenty of time to think it through, (also, plenty of time to WORRY). With that worry building I would think someone would want to be in and out of there as fast as possible. Check for any headlights, then turn down the driveway staying against the bank. Stop just before that first picture you took. Turn off lights but leave engine running, (restarting car can be heard louder then leaving it run). Drag/carry body, (which should be wrapped in plastic sheeting to keep vehicle "clean"), and leave it. Plastic collects fingerprints so take it with you to dispose of elsewhere.
Thinking it through this way leads me to think mutilation was attempted at the first scene, (possibly up Pitcher Canyon/Mission Ridge area??) Can you make it into Beehive Lake yet? Maybe up that way could be the BIG scene???