Yeah, but it's all in one chapter. From the episode where he makes it into the cave and talks to the Three-Eyed Crow, ending with the "...you will fly!" line, there is only one more Bran chapter, which is a general "time passes" episode - the book equivalent of a training montage. While his contribution to Theon's arc was a thing, it was more about Theon, with the reader left to infer from the obvious clues that it was Bran talking to him, rather than the hallucination or divine revelation Theon believed it to be. That didn't have much to do with Bran's arc, and the timing puts it way later anyhow.
They were attacked by undead near the entrance to the cave, but I think they were more typical wights, rather than skeletons. The latter made a nice change of pace, like these are a more dangerous kind that you find deeper in the far North.

Honestly, at this point, I'm wondering what they're doing with Brienne, who isn't much more significant to this point, however much screen time she's had.

Actually, it was drawn out more on the TV show. In the book there was an attack, Mance ran off to deal with it, Jon poked his head out to see what was going on, and watched a bunch of Westeros knights and armsmen kicking wildling ass long enough to ascertain that it was Stannis, then just went back inside the tent to wait.