I've never read Time For Yesterday. Is it good? I don't read the books. It's not canon, so, to me, I've never felt it necessary to put forth the effort.
Why does it matter if the books are canon? There are some really good stories out there.
Also, "put in the effort" is the wrong way to go about it. If you read them, it should be because you want to enjoy those stories, not because you "have to endure them". Which, really, is, what the problem is with the General Audience and a heavy "necessary to know" continuity. The General Audience isn't interested enough to want to watch everything and catch up on continuity, so, for them, it would be having to put in effort.
One Day I hope to be the Man my Cat thinks I am
Where are we going? And why are we in this Handbasket?