Good question. No, we don't know. Nothing about tire tracks has been made public.
As for earlier discussion about which doors were locked, following is the link to Donald Stone's interview where he states that Kenneth's padlock on the outside of his camper was unlocked. Doesn't say it was broken, just unlocked. He said KR usually locked it while he was gone, so DS entered assuming he was there.
http://www.dailymail.co.uk/news/art...-feet-shot-head-reveals-man-horror-scene.html
It was in this interview that DS also said KR had "Brownie", his vicious pit bull. Like with the Manleys, it seems unlikely if DS was the killer that would mention this to LE. He would be incriminating himself as someone who went there frequently and knew the dog. JMO. Same would seem to apply if DS knew the killer and was protecting them. Not the kind of information one would share unless you're really dumb. Ditto for sharing with LE information about security cameras and locked doors. Usually, giving that kind of info to LE would be an effort to help them find the killers.
That said, I think DS has suspicions about who the killers are. If CR Sr. and KR were selling MJ, he might know who they were working with. JMO, he knows something he thinks is important, that's why he's so nervous. Probably knows he'll get killed, too, if they learn he has shared anything about them to LE.
