Why on earth did Jaime take almost all of his 2-3000 horse with him into Whispering Woods? Him personally leading the column can be chalked up to his desire for glory & his impatience, but why did he think he needed all his men to tackle what he imagined were only a few hundred raiders? Jaime is no coward- surely 200 knights & 2-300 light horse would have been sufficient for the mission.

So here’s what happens with the Whispering Woods. Jaime’s been chasing Marq Piper and Karl Vance with a couple hundred men, and then Brynden sends in a couple hundred men in Tully colors for Jaime to chase. Jaime chases them, Brynden’s outriders bushwhack his outriders, and then withdraw. 

Jaime now knows that there’s a larger force than just the couple hundred he’s seen so far, so he decides to go with the tactic that worked at the Golden Tooth and under the walls of Riverrun: overwhelming numbers. The Riverlanders may know the terrain, but if he can throw in enough manpower he can make up for that, using his sheer weight to counter their ambushes, prevent escapes by blocking routes, etc. And because it’s all cavalry, his larger army is still just as mobile. 

It’s not necessarily a terrible plan for counter-insurgency, as long as the only thing he’s got to worry about is guerrilla bands of Riverlanders. Unfortunately, he doesn’t know the Starks are there.