[Lmn55d]

hmm, I'm gonna say fold the river. When he checkraises the flop lets say his range is a straight draw, flush draw or pair+. His check on the turn could mean a few things. He could be on a flush draw and not want to be raised. He could have a pair of 6s and be check/folding. He could have a pair of Ts or Qs and not want to be semibluffed and is trying to induce a bluff. Or he could be going for a checkraise.

When you call the river, it seems that you are hoping he was on a flush draw, right? I cant see him betting a pair of 6s there. The thing is I think a flush draw follows through on that turn a lot and might not bluff the river. I don't think you're good 1 in 6.25, but I'm not positive.