[svat]

I have read through about eight pages of one of Knuth's most recent pre-fascicles.[1] It took me about a month (on and off). I did all the exercises (trying the harder ones for at most a couple of hours or so before giving up), wrote programs to explore the things introduced, etc. It was good, quite doable, and a lot of fun. (Also, I found a few errors and got some of those Knuth checks.)

The best way to view Knuth's project with these volumes is that takes in all published computer science on a particular topic, digests it, and outputs into the books some sort of "summary" of the field, or whatever he considers the most important bits, but still organized as readable/learnable textbook material, and in the way he thinks makes for best exposition. (In other words: he's doing his best to explain, and his best is very good indeed. Often Knuth's writing is clearer than the original papers, and a lot more fun.)

[1]: http://www.cs.utsa.edu/~wagner/knuth/