Should Robb have won after the Camps?

[Catastrophe]

Robb's series of misfortunes after this point are about as realistic as Theon marching across hundreds of miles of the Northern interior, with a bunch of Ironborn warriors who can hardly mount a horse, to capture the 8000 year old capital of the North that as far as we know has never been conquered before.

On the battlefield, Robb was extraordinarily successful. His misfortunes were largely a result of politics (specifically, losing the support of the Freys and the Karstarks). His few tactical failures were caused by circumstances he couldn't have possibly predicted (Balon Greyjoy's suicidal decision to attack the North, even though there's no possible way he would've ever been able to hold it; Roose Bolton deliberately sending Northern troops into unwinnable battles). Beyond all that, Robb's main problem was that he didn't have a clear long-term plan for accomplishing his goals. He was a truly phenomenal tactician, but a poor strategist. Given all of these factors, I don't find Robb's misfortunes to be particularly unbelievable.

Regarding Theon's capture of Winterfell, it makes sense, given that the castle was only guarded by a skeleton crew at the time and Theon had extensive knowledge of its layout. If anything doesn't make sense, it's that Ser Rodrik would leave the castle almost completely undefended for the sake of defending Torrhen's Square (which was strategically irrelevant, and probably could've been taken back with less than a third of the men that Rodrik took). That was one of the worst strategic blunders in the series, far worse than Edmure's "mistake".

When it comes down to it, a truce was never on the table for Tywin. The way he deals with enemies is by obliterating them. Like he stated many times, as long as there is enemies in the field, a war is not over.

However, I do think that Robb should have made peace after Oxcross simply because he had Tywin in a very precarious predicament. Plus getting Sansa back and using her for a political marriage would have been a huge plus. Not to mention that Robb would have "won" and avenged his father because he now would have taken over half of Westeros and cheated the Lannisters of having a unified Kingdom. Also, this would give him time to muster up his army again because eventually he would have to come face to face with the victor between Stannis/Tywin/Renly as we all know they wouldn't accept a fractured realm.

I think Robbs honor is what made him push too far in this campaign. He felt like he needed to kill Joff himself in order to avenge his father when in reality he should have been a wise King of the North/Trident and laid down his sword when he saw that Tywin no longer had a way out.

Robb's goal was never to kill Joffrey himself. His goal was to force the Lannisters into a position where they'd have no choice but to grant the North and the Riverlands independence, he even sent peace terms to King's Landing stating as much. Of course, there's no way that Tywin was ever going to give up half of Westeros, and even if Renly or Stannis had taken the Iron Throne, I strongly doubt they would've agreed to Robb's terms either.

From a strategic perspective, Robb's mistake was trying to defend the Riverlands and incorporate them into his new kingdom, since they're open to attack from both the Westerlands and the Crownlands. The only way he could've achieved his goal was by withdrawing his forces back into the North and sealing his borders. (Obviously, he would've needed to do this before the Ironborn took control of Moat Cailin and Winterfell. Once those castles fell, his cause was all but lost.)