The abuse of the corpse could be because of the way he disposed of tge body. A local funeral home had multiple charges after not properly burying or cremating bodies. It's a vague statute that covers just about anything post mortem.
I'm not saying he didn't do anything post mortem, but it's very possible it was because she was bound and in a shallow grave.
He likely had a "kit" with him that got dumped out in the field, and he was too focused on his plans to gather them. Then getting her out was his main concern. I'd like to believe she never made it to tge barn, but in all likelihood she probably did. He probably went to retrieve his items, saw LE and determined he had to hide her. Can't go North, they are looking, so he went West and South to bury her.
The water bottle with straw and sandwich is what makes me believe she was in the barn. The one pair of regular panties does as well.
I think startling someone with a motorcycle and maybe crowding a lane could make them swerve and crash. This is horrific, and so incredibly scary. Then you factor in reports of craigslist ads.
I believe he is opportunistic, and maybe he had previously used ads to draw people to him. I'm thinking he saw her riding by and maybe was stressed because "stress kills" saw an opportunity and couldn't resist. He wasn't thinking ahead, didn't expect a quick search, and then spun a story.
I'm not sure he directly lies, he said he didn't touch RG sexually, that may have been true. He didn't have a chance because his plan was thwarted.
When he spoke to LE, he may have not "killed her" as of that moment, and related the "I haven't stolen anything" to her bike and phone. I suspect to him women have no value, and did not feel she was "anything". There is another scenario to the I didn't kill anyone, and if the autopsy is released and her cause of death is the same as Neveah Buchanan, well, let's hope it's not. Any scenario is disturbing.