My interpretation was that he dragged her from where he parked, down the cornfield pull-off because it is basically dirt and grass, and then put her over his shoulder to take her into the corn rows, where maybe it was harder to drag her through. Just my guess.
I agree totally with you on this point, that he dragged her from the car towards the corn field. At some point, this became too difficult, so he hefted her over his shoulder like a sack of feed, and walked through the corn rows, her body and his shoulders pushing aside the thinner corn tops, his slender frame slipping through the rows.
The only fine splitting of hairs left to "sluth" is did he drag her as a professional fire fighter would, his front to her back and his arms around her torso as he walked backwards, dragging her heels along the ground as he was on foot (his)?
Firefighters use this drag, because it is the most efficient way to drag a limp body you can't carry. If light enough, over the shoulder works well. BTW, I have worked with "small" frame Phillopino and Latino men who can carry close to their body weigh, or more, over their shoulders. Back in the day (1950's to mid-60's) this is how Stevedores and Longshoremen off loaded cargo from ships, by hand).
This, presumably, preferable to his having dragged her "by car". This meaning that he drove the car with his right hand, holding the foot of the now bloody body with his left hand while dragging it along. This as he drove up the service access road between the corn fields, to the drop site patch of corn, only then carrying the body to and through the rows, (I grew up in Louisiana, and you would be shocked at what you see people transport this way, including oldChristmas trees dragged up to the dump, and Livestock on a lead.)
OR. did he flop her body from the trunk on to the ground (or rape and kill her on the service road behind the car), and then drag her, while pulling on a single leg held by the foot, to the edge of the corn rows? (Lilerally "by foot")
Parse the few words in the warrant all you want. At this point, this is the equivalent of attempting to understand the entirety of ancient Egypt solely by the writing on the Rosetta Stone!
LE is sitting on a veritable mountain of evidence that we may learn about at trial or at pre-trial hearings, or maybe never.
Only time will tell.