I don`t understand. Why is Sheriff McAllister a suspect? I don`t say he couldn`t be Red John, but I don`t know what made Jane think that McAllister could be RJ. He appears in an episode which has nothing to do with Red John and, yes, he has  weird behavior. His attitude with Van Pelt made us all believe that he could be the killer (who murdered that girl from the 2nd episode), but I think no one found any link between him and RJ.
I mean, if he is RJ, he most certainly does know that Van Pelt works with the CBI. The whole scene on that road when his harrases Van Pelt would make no sense, since he knows very well that she and Rigsby are part of Jane`s team. So which could be the link?
What made Jane put him on the list? This isn`t a random choice, that`s obvious, but I just can`t see the reason.