Is also worth a watch. Though I found that I've had to restart it a couple times over the years. Category theory, like many more abstract topics, is really hard to get a handle on. I've restarted those YouTube videos and have found them much easier this time around since enough of the basic category theory concepts are now in my head (though not fully understood with regard to purpose, implication, or application).
We've got Dr. Baez, Dr. Spivak, and several others who are much more familiar with the field and its applications participating in the forum now.
The lectures present the same material as the text book but in a slightly different order and with additional examples (what you'd expect from a lecture series). Technically, reading the lectures is sufficient for understanding the chapter at least at a high level. Reading both is fantastic because they complement each other (Dr. Baez assumes some of their theorems and propositions, but introduces others).