I'm sure much of this has already been discussed. I've seen it written in almost every episode/character/etc summary that Charlotte was not "awake" in the Sideways world, a fact which seems to frustrate a lot of people as she played a fairly significant role there in moving along other characters. I'd like to argue that Charlotte was, in fact, "enlightened"-- and that we saw her awakening, way back before we realized what we were actually watching. Hers was the first enlightenment we saw. Here is what I think happened:
When Charlotte was dying of the time-travel sickness, she saw the literal flashes of her life before her eyes. She talked as if she was a child about not having chocolate before dinner, etc. What we thought was the most significant moment in her death scene was when she saw herself as a child seeing an adult Daniel Faraday in Dharmaville tell her that she had to leave The Island and never come back. This was significant because this moment hadn't actually happened yet-- the adult Daniel Faraday would not approach Child!Charlotte until after Adult!Charlotte was already dead and the rest of the time-jumpers had become stuck in 1974. So... Charlotte, in her dying moments, remembered something that had *yet to happen*. This means that the flashes before your eyes when you die, in the Lost universe, are really *everything* that happens to you not before you die but before you are awakened. We learn this from Juliet (which I'll get to in a second) but also from Charlotte herself with her dying words (and that episode's title)-- "this place is death!" Charlotte's comment was not, as we thought at the time, about The Island, but about the world she was heading into in her final moment, the Flash-Sideways world. Who better to explain that to us than Charlotte, our cultural anthropologist, who makes the biggest discovery of her life through her own death? Charlotte tried to tell Faraday and the rest of the time-jumpers what she had discovered but they couldn't yet understand, as they were still amongst the living. It's a perspective misinterpretation akin to Richard Alpert calling The Island "hell" and making characters (and us) suddenly wonder if he was right. So, fitting this into Juliet:
When Juliet died, almost the same thing happened. As we know, different souls require different things to lead them to a moment of enlightenment. Ben required violence, Kate and Claire required motherhood, Desmond and Charlie needed romantic love, etc. Charlotte lucked out-- knowledge and truth were what she sought her entire life and that was what led to her enlightenment. She died and was let in instantly on the secret, as a sense of discovery was her defining characteristic. Juliet, however, had not yet encountered Sawyer in the Sideways world. She still had things to work through-- issues that required an ex-husband in Jack and a fictional child in David. So, when Juliet's life flashed before her eyes as she died and she saw another version of her life, where she has her maiden name because she never married that scumbag and where there's an alternate version of their lives, she thinks hey! it worked! We created a parallel universe or we fixed time or whatever because all's looking good here, James! And that's her final thought, which Miles relays to Sawyer. What actually happened was that Juliet saw both worlds, right up until the moment she was enlightened. When she says "it worked" in the Sideways world, she becomes aware of what it truly means because now she's seen Sawyer, had her moment of awakening, and understands that they are dead. So, back to Charlotte for a moment.
Charlotte, we'll note, is not a cultural anthropologist in the Sideways world-- she's an archaelogist. Her job now is to literally dig up the past and that's what she does. She helps those around her towards their own awakening. She and Miles-- whom I think was awake, as was his father, and it likely happened at the same time-- conspire to help their fellow time-hopper Sawyer. Miles helps him with his daddy issues, which Charlotte literally digs up out of his bureau. We hear that Charlotte is the facilitator of Daniel's awakening. She helps out at Eloise's concert by waking up Charlie-- a bit of a wink as she helps him regain consciousness when he died trying to keep her freighter from reaching The Island. (There's a lot of that in the Sideways-- Pierre Chang as the MC at a night honoring Hurley, trying to boost his confidence, after Hurley got Pierre and Miles to reunite in life; Daniel and Charlie helping Desmond, after he helped them, etc.) Charlotte doesn't enter the church because she, like Ben, wants to hang in the Sideways world and experience what she didn't get to in life with Daniel. But Charlotte wasn't unenlightened-- rather, she was, as she usually was in life, the most aware in the room. And those are my thoughts. :)