Gawyn's involvement

Here is how Gawyn is already involved in the siege-war of the White Tower. Gawyn is acting on orders from Elaida that were given to him in/after his POV in the prologue.

In the CoT prologue, we see that Gawyn is trapped in Dorlan, a small town on the eastern side of the Erinin, along with a bit over 300 Younglings. Also Covarla and the 11 AS under her are in Dorlan, along with the messenger Narenwhin (Tarna and Katerine left in/after the CoT prologue).

***CoT, Prologue, "Glimmers of the Pattern"

The newest problem was that an army lay between him and Tar Valon, now. At least twenty-five thousand soldiers on this side of the River Erinin and, he had to believe, as many on the WEST bank...

...Any army would take notice of upward of three hundred men on the move, and the rebels would have no goodwill towards the Younglings...

...Gawyn would not be sorry to see either leave. Tarna had ridden into Dorlan barely a day after the mysterious army arrived, and however Aes Sedai determined these things, she immediately displaced Lusonia Cole from her room upstairs and Covarla Baldene from command of the ELEVEN other sisters already in the village...

***
These quotes give the location of Dorlan and all the Elaida-aligned forces who reside there (the EAST side of Erinin), and also the number of younglings there (~300). The 'either' Gawyn refers to in the 3rd paragraph are Katerine and Tarna, who do leave Dorlan (for the Tower). This tells us that only Covarla and her 11 AS plus Narenwhin are left, leaving us with (interestingly enough) 13 AS in Dorlan.

There are actually no hints or proofs in Glimmers regarding what the orders for Gawyn may be, but suffice to say that Narenwhin has orders from Elaida for both Gawyn (plus Younglings) AND Covarla (plus Sisters under her). Now look at the first description of raids on Egwene's (Bryne's, rebels, whomever) forces, from Egwene's POV.

***
CoT, Ch 16, "The Subject of Negotiations"

...Without any doubt, that smoke plume on the far bank rose from burning wagons or supplies. Pinpricks, yet those pinpricks came every night, sometimes one, sometimes two or three, till everyone looked for smoke first thing on rising. Hunting the raiders down had proved impossible, so far. Sudden snow squalls flared around the pursuers, or fierce freezing night winds, or the tracks simply vanished abruptly, the snow beyond the last hoofprint as smooth as fresh fallen. The residues of weavings made it plain enough they were being aided by Aes Sedai, and there was no point in taking a chance that Elaida had men and maybe sisters on this side ofthe river, too. Few things could please Elaida more than gettting her hands on Egwene al'Vere.

***

This quote tells us 3 key things: first, that the 'pinpricks' have only occured on the opposite side of the Erinin to Egwene's camp. Secondly, that the raiders have AS and soldiers, and finally, Egwene believes (incorrectly it would seem) that there may also be soldiers and AS aligned to Elaida on Egwene's side of the bank also.

Egwene is on the Dragonmount side of the river, which is the western side. So the raids must only have taken place on the eastern side, Gawyn's side, implying that Gawyn and his Younglings are responsible for these minor nightly offenses. The fact that the pinprickers (lol) have AS help strengthens the notion that the Tower-aligned forces from Dorlan are who is responsible for the pinpricks.

In saying this, i have assumed that no sizeable force is able to leave Tar Valon and set up camp to do the raiding. IMO this is a fair assumption because Bryne is tightly guarding all the bridge towns (although not the harbours), the Tower sisters can't travel, and also Gawyn's quote from above about "300 men moving get noticed" supports the asssumption. So the only forces which could do the pinprick offensives must already have been stationed outside of Tar Valon at the time of the rebel army's arrival.

Egwene's (sensible) belief that there are also Elaida-aligned forces on the western side is false, as is implied on the first page of the final chapter of CoT. (NOTE: her belief is false, but is sensible because she is assuming the worst and planning around that... so i aint contradicting myself)

***
CoT, Ch 30, "What the Oath Rod can Do"

...Elaida's raiders continued to strike with impunity on the other side of the river...

***

This is the only other reference to raiders i have found; no-one ever mentions that there have been raids on the WEST side of the Erinin. If somebody finds evidence to the contrary, by all means shoot my theory down. ~grumble~

Apparantly some are wondering what Elaida's orders are, or what Gawyn's involvement in the Tower siege will be. But we already know (so far); Gawyn is leading/organising the raids on the rebel AS army on the eastern bank of the Erinin, with 13 AS from Dorlan to cover his tracks. The pinprick raids are likely small groups of younglings (20 to 50 maybe) with an AS or 2 to help escape, (in light of Gawyn's comment about the difficulty of moving a force of 300, the raiding parties would have to be smaller than 300).

This may be a null theory to some (i.e. "Theory? i thought it was fact!") but it may be a new idea to others.