In The Beginning should not be watched in the beginning. It would be a major spoiler. I agree with the commenter who said it fits very well just after 4x09 Atonement.
I’ve reverted Lurker’s Guide’s change to the position of 1x14 TKO. Certain events in the episode were said to happen months after certain events in an earlier episode. TKO is already positioned about a dozen episodes after the earlier episode. I don’t really see a need to move it further.
5x22 Sleeping in Light should be the last thing to watch indeed.