Notice the bit Brandon wasn't sure about is how much Mat was behind Egwene and Rand, and the bit he was sure about is that Mat arrived in Caemlyn 30 days before the book's climax.

That's fairly simple to puzzle out, really: Jordan seems to have timed things so all the main characters will go through something momenteous around the same time, right before TG starts. Rand had his epiphany, Egwene was made Amyrlin and went also through big character development. We can even say Nynaeve also went through a major turning point and that may not be over (a big confrontation with Cadsuane over how she's used her would be my guess. I think Nynaeve might decide the time has come to force all the AS to recognize her authority over them as the most powerful AS present. It's like Aviendha: Cadsuane is waiting for Nynaeve to refuse to bow down to anyone not acknowledging her a full sister) It's not very hard to guess Mat and Perrin (and maybe others) will have parallel "big moments" happening on the same day (one will be Aviendha going through Rhuidean, or something happening with her in the three-fold-land afterward... people seem to have forgotten that there's full of Tinkers around Rhuidean and that many Aiel have fled back to them... it's only a matter of time before these Aiel tell the Tinkers how they've learned about their past, from whom and how he knew.... the Tinkers will want to go to Rhuidean, as maybe their (silly) Song can be found there, as there's a device that tells their past to chiefs and WO.... That's what Aviendha will have to deal with, and make a decision over, IMO). Aviendha will return west with the Leafers, and they will know the Song are actually songs. It's not a coincidence Aviendha was horrified at refugees, and hunger in TGS. She's bringing to Rand the solution to hunger as Sung-crops, and now that he's "healed", he can start to heal the land with the "children of the Dragon" as they were in the AOL... As for the songs themselves, it sounds like it's Elayne who has the device in which they are likely recorded - and again Aviendha knows about these devices (the AOL i-pod, or the AOL library).


It seems Jordan intended to wrap up all the storylines before bringing them together soon, as TG starts.

It's also kind of obvious Brandon was so certain Mat was 30 days from the climax because he knows something momentous happens to Mat on that very day when his oath to Verin is fulfilled, when he can leave Caemlyn (and decide to open her letter, now he's not bound by it anymore...), and that this event is timed with Egwene and Rand's own big moments. It sounds very likely this is the day Mat will Travel to Ghenjei and enter the Tower at sunset, and in the night while he's rescuing Moiraine, Rand will come to Dragonmount.