Wow, this is super cool, everyone sounds right, the gang's all here, this is going to be a good story and I can tell I'm going to like stories by you in general. That's cool that River and Kaylee have a secret poker alliance when River is lucid enough, you can't lose with River helping. :) I'm surprised the others let them play together though, since River can read things in that way. Great start. The only thing, and its a little thing, I don't think I've ever read a story where Mal is referred to in the narrative as "Reynolds". Its not wrong its just different. I can't wait for the next chapter! I rarely start new things by new authors but this was a welcome exception.
Riona

Nice start! I'm looking forward to seeing where this goes. And what happened to Mal. And what they're going to do next. Oh snap!

I don't think your descriptions of every character are necessary, though. You can usually assume that if someone's reading fanfiction, they're already familiar with the main characters. In this case, I think sentences like "Even though Book was old enough to be River's grandfather he was a powerfully build man and he and Cobb, a man in his prime, lifted weights together every day in the hanger" break up the flow of the story, because I want to get to something I don't know.

Otherwise, nice job! I hope you update soon.

Good job with the story - I'm looking forward to more. Don't miss the Firefly marathon on the Sci channel all day today!