From what I've read, it's my understanding that the properties around the crime scene were vacation homes that were not occupied at the time, other than the RL property.
On the day the girls went missing, Feb 13, it's my understanding that RL was arrested for violating unrelated probation conditions that had been in place since a 2014 prior. My understanding is, that due to the arrest on Feb 13, RL was detained from being on his property during the time of the events that led up to the discovery of the bodies on Feb 14. IMO, it is possible that searchers were not aware of this until after the fact and had naturally expected that he would have checked his own property during the searches and therefore did not trespass on his land to conduct searches.
What a bad break for RL (but also a solid alibi), and what a lucky break for the perpetrator(s) of this crime. Or was it? Was RL just unlucky to be caught violating probation and arrested that day? Or, did someone close enough to him to know or influence his actions on that day that tip off LE, effectively causing the arrest that kept RL away from his property? Another possibility exists, in my option, but requires implication.
This is my amateur conjecture only. It was spurred on by my minds need to reconcile why the bodies were not discovered until Feb 14, and how the perpetrator(s) were seemingly able to have unfettered access to the RL property.