I am quite interested in modifying a few perks and/or adding some perks. Is this a functionality that is included with the CK? I see no mention of it on the Wiki, and exploring the CK by itself yields some results about perks, but nowhere that seems like a place to add/modify/remove them. If it is not doable within the confines of the CK, is there any information out and about that I could be pointed to that might give me an idea of how to go about this?

In the Object Window (the one where you access all the game's items), expand the Actor branch, then click on Perk. The list to the left should now show all of the perks. Right click them to add/modify/delete.

Clicking the top menu bar button titled Character, then clicking Actor Values, will bring up a dialog window where you can select major skills and edit the actual perk trees linked to them.

Ah there we go. I did not notice the 'Perk Tree' button under Actor Values. Thank you very much for the quick response!

You're most welcome.

There are some things they didn't entirely botch with this mostly useless piece of software.