The 2e Guide to the Ethereal had the most details, and a rather interesting castle perched on the exterior boundary of the demiplane of time. The 3e MotP has the temporal energy plane listed in the back as an alternate plane, and its description is similar to the 2e demiplane (and I mentioned 'Temporal Energy Plane' as an alternate name of the Demiplane of Time in Dragon 353 just to link them together in the space I had).
I ended up using the details in GttE in my own campaign to brief but pretty good effect, though once inside I had to come up with most details myself since there's not much that has ever been written on the inside, beyond the mentions of manifest timelines, roiling windstorms, temporal effects, etc. And as far as monsters go, I stocked it with Chronotyryns, but largely avoided having the PCs exposed to anything in the interior for very long so as to spare me having to run random encounters in the maelstrom and so they could get to a "safe" location deeper inside.
While there was a 2e "Chronomancer" book, that was one of the Mayfair products that TSR got a hold of after they sued the pants off of them. What that book describes has little to no relation to the 2e Demiplane of Time or the 3e Temporal Energy Plane, but given that it was written by another company I think it's certainly understandable that it doesn't come off as cohesive. I've briefly read the book, but didn't think too terribly much of it, and because of the lack of cohesion with the material already in D&D prior to that, I've never used its contents. Of course, if it works for your uses, then go for it.
