Why doesn't River speak in "Our Mrs. Reynolds"? Not sure, but wonder if it's because she can tell that Saffron isn't what she seems to be, but can't figure out how to communicate that to everyone else. There's actually a funny deleted scene from that episode wherein she does quite a bit of talking. If you don't own the DVD's, you can read the script, probably from a link at the homepage on FireflyFans.net. I'd tell you about it, but don't want to be a spoiler! *g*

I wondered about the Simon/Dr./hill people thing as well. I think JayTee had it right. The hill people figured there was something on the ship they'd want, but didn't know what, til they heard Mal talking to Simon.

dunno why river doesn't speak in MrsReynolds. In Safe you can hear rustling in the bushes when Mal is talking to Simon near the cattle pen. It's not revealed in the show but one can extrapolate that the hill people are spying on them and overhear Mal calling Simon Doctor.