There's one detail about this case that keeps gnawing at me, but I haven't seen it addressed much.
It seems rather likely that Crystal wasn't driving her car when it got a nail in the tire and went flat out on that stretch of highway. Granted, all of her stuff was in there, but I don't think she was. The flat tire was a big surprise and an unpredicted obstacle in the attempt to cover up and hide this crime. It appears that the car was being taken to a different location in an attempt to create a buffer zone from where the crime occurred to where her vehicle would ultimately be found. This would have transferred the search zone over 25 miles away from Bardstown, and possibly a lot further.
Now, where would this car have been headed ? Elizabethtown ? Some other small town ? Close to an ex-boyfriends house ?
The person that was transporting the vehicle, how did he/she plan on getting back to Bardstown after the car was abandoned ?
I think I may have the answer. Two people involved, one driving her vehicle, one following behind.
When Crystals car got an unexpected flat tire, the person following simply pulled over, stopped, and picked up the driver right there on the side of the road. It would have been too risky to put on a spare tire there on the shoulder, since a highway patrol could come along at any minute.
Even though planting her car in another town and staging a crime scene was part of the plan, it turned out to be a huge failure, so that part of the plan was abandoned. Either way, the person driving her car was going to have to make it back to Bardstown.
It seems like to me that at least two people have to be involved in this caper. They need to look very seriously into any women that Houck may have known and communicated with. To me, this almost screams out a female helping a male get rid of his troublesome girlfriend.
Motive? Well, maybe he wanted sole custody of their child. Maybe he didn't want to be saddled with child support payments for the rest of his life. Maybe he just liked this other woman better and wanted to start up a family with her instead. IF it turns out that Houck is behind this, then it appears to be premeditated and planned out in advance, but I still think he had an accomplice, simply due to the attempt to move her car far away from the scene of the crime. Somebody picked up the person driving that car when it got a flat tire, and even if it hadn't gotten a flat tire, that same person was going to give him a ride back home to Bardstown.