I think people are missing the point of Serenity, which is one of the problems I have with the D20, or really any rules system converting the show and film into a game. The problem as I see it is that you have all of these questions. The show lacks real hard science, but has an edge of realism. The idea is that this is a plausible future where the majority of travel is done between the various moons which are realitvely closer than the planets. Interplanetary travel is still possible, but time consuming meaning that most people are essentially bound to their planet or moon of origin, except for those that can afford to travel. Adding in hyperspace or FTL cheapens the feeling of the series which is about beating around the 'verse in an aging transport ship and dodging the law. The setting is a gritty wild west kind of solar system. With podunk towns and isolated people making due on the rough fringes. Add FTL or other super-high tech stuff and you lose that. People can get around willy-nilly, why would anyone move out to the edge, and how would that be difficult if you could just hop on the next transport ship to the Core with little or no wait time. The fun is that it's gritty, no aliens, few lasers, low-tech story and character driven sci-fi. To each their own, and games were made to be adapted to the style and liking of the players and GM, but for my own two cents if you want to play a game based off of Firefly/Serenity do so, if you want something else use GURPS or D20 Future or Traveler in one of it's many editions and just draw what inspiration you want from whatever sources at your disposal. Just don't belittle a good series 'cause it doesn't fit with your game, if it's not the way you want it, change it, but that's not Serenity.