Oookay ... some more thoughts:
1.) The ME from back then is probably deceased by now, but what about anyone younger, who worked back then in the morgue? Such a person would maybe remember at least some details.
2.) I try the whole time to get an overview over the area, but of course, Google shpws me the situation today. I wonder, where Hwy 12 leads to and whether there was a faster alternative road back in the day. Because if we follow the idea of a non-local, he had to have some reason to be on that road that night. Orofino doesn't appear that big to me, so would there be something bigger behind Orofino, along Hwy 12? A possible destination for any kind of business traveler? I remember such a case in Ohio, also in the 50s, that made absolutely no sense to me till someone told me, Goodyear was in Akron.
3.) Are there any hints, where those boys who gave Lonnie a ride back then, are today?
4.) @Robin Hood: Did you check the FBI vault site? Had no time to do so, but if Savage was involved in something bigger during his FBI-years, there is maybe something in there.
5.) A lot of meat in the area means, also a lot people who would know how to slaughter an animal in the area.
6.) @Kline: If you are around there and have time, can you shoot some pics of the crime scene as it is today?
7.) If this guy did it before and took non-local boys, for example carnie boys, it could be, they were reported missing at the next station of the fair. So what would be the typical next station?
8.) I doubt, that rapes of boys were reported at all. Homosexuality brought stigma back then, even to the victims of homosexual rape. But if those things would happen, rumors would go around in school. So someone from high school in these years would maybe remember rumors about strange guys hanging around, maybe with a car. Or about someone, who changed from one day to the other. In the Ohio case someone remembered, there were allegedly two guys hanging out near the school offering money for sex with boys, but that was never reported to police. So who has an old yearbook?
Just an unsorted list of thoughts.
Peter