
And here it is, the episode I've been dreading to review for a few days now. It's very difficult for me to assess the writing of this episode, because the cabin storyline is either a stroke of genius or a complete disaster.
No matter which it is, it's still fun to watch.
Cabin Fever breaks the flash-forward trend of Season 4, presenting a series of flashbacks covering Locke's childhood. As a premature baby he was given up for adoption. As a toddler he was tested by Richard Alpert. As a young teen he was pressured to pursue his interest in science (thanks to Mittelos Laboratories). In all three cases Alpert had an intense interest in Locke's progress.
On the island, Locke receives guidance from a dream featuring Horace Goodspeed. Locke, Hurley, and Ben stop by the DHARMA corpse pit to retrieve a map off Horace's corpse, then they trek into the jungle in search of the cabin.
This is where the "brilliance vs. disaster" part comes in. As an audience we're led to believe Hurley has some sort of ability to locate the cabin. After Locke scores the map he suggests that Hurley return to the beach. Hurley takes exception to being tossed aside now that his "ability" is no longer needed, but Locke insists he was simply looking out for his well-being. Hurley isn't buying it and chooses to stick around. As Hurley defiantly trods ahead this little exchange follows:
LOCKE: What?
BEN: He actually thinks staying was his idea. Not bad, John. Not bad at all.
LOCKE: I'm not you.
BEN: You're certainly not.
Okay, so any good story has some measure of ambiguity, but there's ambiguity and then there's Have-Your-Cake-And-Eat-It Too Syndrome. It's frustrating enough trying to determine who inhabited the cabin (Horace suggested in the dream it belonged to Jacob, but who was responsible for the dream?) or what its purpose was, but now we have no idea whether Hurley's abilities are a factor we should even care about. Even with Horace's map Locke couldn't seem to find the cabin until Hurley stumbled upon it — but it's anyone's guess if that actually means anything.
Locke walks into the cabin and finds Christian (well, Man in Black in Christian's form) sitting there with a contented Claire. Christian tells Locke he needs to move the island and there's our cliffhanger.
So at this point in the narrative, the only way I can reconcile the cabin storyline is if I imagine it as a contested location between Jacob and MiB, perhaps a metaphor for a game piece on a board (and we know how much they like games). Jacob controlled it in Season 3 (hence the ash ring keeping MiB out), then it was contested in early Season 4, then it was controlled by MiB by Cabin Fever.
The metaphor might even extend to the cabin moving locations, indicating the ongoing tug-of-war between the two. If that sounds like a stretch, that's okay — so is every other theory I've heard. Granted, my "game board" metaphor doesn't explain Hurley's possible ability to locate it, or even why Jacob said "help me" in Season 3, but I'm content with those pieces missing and I'll cut my losses.

I feel like saying O'Quinn performance was abysmal just to check whether anyone's paying attention. But I can't do it. There's no such thing as a lackluster performance by TOQ, especially in a Locke-centric. However, island Locke was mostly one-dimension in Cabin Fever. A man determined to forge ahead and find the cabin at all costs.
In fact I'd almost have to give equal credit to Emerson and Garcia for making the island storyline as entertaining as it was. The Locke-Ben dynamic and their ongoing power struggle is intriguing on its own, but when you throw Hurley's humor into the mix it goes into a third dimension. I howl every time they get lost and argue over who's following whom, to which Hurley replies, "I'm not even in front!"
Case in point: one of my favorite scenes has no dialogue. None. It's just Hurley and Ben sitting next to each other in the dark jungle. Hurley breaks out an Apollo bar and unwraps it while Ben watches intently (of course he can't bring himself to express a desire to share it). Hurley's good soul prevails once again, as he tears off one half and gives it to Ben. They both chomp pensively on chocolately goodness. Part of me wishes Locke had gotten a piece as well, for he would've been the third "nom" in the "nom nom nom" sequence.
Caleb Steinmeyer (teen Locke) was about average, as was Charles Henry Wyson (toddler Locke). Deductions for the first scene with Holland Roden (young Emily) and Rebecca Tilney (Mrs. Locke), neither of which were all that impressive.

I think the only major bump in the road in this episode is the opening scene with young Emily Locke, and by that I'm referring to the writing, acting, AND directing. It's cheesy by LOST standards to think Emily would run out of her house and onto the street, completely oblivious to the car barreling toward her. It felt like the opening to a low-end episode of The X-Files. Maybe some different angles would've sold the plausibility a bit more, but that's easy to say in hindsight.
After that snafu things get substantially better, starting with Locke's encounter with Horace in a dream. Love the way that sequence loops with the same tree being chopped repeatedly.
Another highlight would be the scene where Richard visits toddler Locke and presents a series of items. This was great coordination between the young actor and the director, because your typical child actor doesn't have a good sense of timing and when to pause. But this is different. There's a chance for toddler Locke (and as a result, the audience) to study and think about each item as it's presented.
Lastly, I love Paul Edward's bold decision to use only one camera angle during Hurley's snack break with Ben. It was nearly forty seconds without an angle change, an eternity by LOST standards.

This is one of the few episodes where my Longevity rating is stuck in limbo, all because I'm still unsettled over the cabin storyline. I still enjoy the moments between Locke, Ben, and Hurley, but if the powers-that-be ever came forward with clear guidance on the cabin mystery my enjoyment of the episode might soar into the stratosphere.
Even if the cabin IS fully explained some day, I don't know that it has much impact or significance on the other elements of the story — that is, unless some fact comes to light suggesting MiB could only communicate with Locke within the cabin at that point.

Some moments are definitely more atmospheric than others. The scene with Richard and toddler Locke is almost spine-tingling with all its cross-referencing implications... a drawing of Smokey on the wall, a compass, a comic book, the list goes on. It helps that Giacchino's music at that moment makes it feel almost majestic.
Locke's dream of Horace is also quite bizarre, even by LOST standards. It feels that way because it starts out completely mundane and if you're not paying attention you won't notice Horace chopping down the same tree twice. It's only when Horace says "hello there" for the second time that it feels like something out of a horror flick.
The tension at the cabin in the final scene is so thick you can cut it with a knife. Seeing Claire was surprising enough — seeing her give a knowing smile to Christian was almost disturbing.