Where did Walder get all these men? He already had assembled 4k men at the beginning of the War, and this was with quite a bit of time as well. Yes, he likely would have been able to raise more men in time, but I can't imagine it numbering more than a thousand men, and these men likely wouldn't be as well trained or armed as the original ones that he had sent.
It would be more practical if Robb just raised more men from throughout the rest of the Riverlands, and even then, he would be getting at most a few hundred men each.

How the actual fuck did Alys get there?
Given Jeyne and Alys's existances, I was assuming this is based on book cannon. She would've had to ride all the way to Flint's Finger (which is on the exact opposite side of the North, sail from there to Seagard (passing the Iron Islands along the way), then go to Riverrun.
In the books, Robb had a big problem in that the Ironborn had taken Moat Cailin. This left him without any ability to retreat to the North, or gather more men from their. Robb's plan was to retake Moat Cailin (which is why his army was all there for the Red Wedding), then go from there. Robb certainly did not have the strength to take Casterly Rock, and after the Battle of Duskendale, and the fall of Maidenpool, at the hands of Randyll Tarly, Robb's temporary security that he had gained in the Riverlands thanks to the retaking of Harrenhal was gone.
Also, Casterly Rock is completely unassailable. Robb has at best, about five thousand men at his disposal at this point, with Roose off doing his own thing in the East. Actually, retaking Moat Cailin, and raising more men now that the harvest has gone, and likely he would get a lot more men who had only been waiting for the harvest to pass, and with Winter coming, they would want to unload as many unnecessary mouths as possible.

Executing Rickard Karstark was certainly not a mistake.
The Karstarks only brought about a thousand men at arms to the table at that point, which is not enough for say, preventing the Red Wedding. Additionally, Robb didn't exactly have any way to rally those men. The men that he had retained from the Karstarks, would've been retained regardless of whether or not Rickard was alive, and those that left, would've left regardless.
And frankly, Robb marrying Jeyne wasn't the worst mistake in the world either as I stated in my previous review.
The much, much bigger mistake was sending Theon home.
Also, wow. Rickard had originally betrothed Alys to Daryn Hornwood, the heir to Hornwood, and now he's secured the Lord of Riverrun for Alys after Daryn died. Given regional politics, I would expect he may try to get Wendel Manderly, or if Robb were to legitimize Lord Hornwood's bastard son, he could still have his daughter wed to the Lord of Hornwood. Or when it inevitably comes up, he might propose Alys be wed to Jon.

So Cersei's showing up next chapter?
I can't wait.
Or is Cassana Estermont's corpse making an appearance?
Either way, I'm sure that it's going to be totally epic.
In all seriousness though, this is perhaps the worst possible solution to Robb's problem, and might just be worse for him than marrying Jeyne.
We need to start with why Robb was crowned. Now, there are many reasons for why the Northern Lords likely wanted independence, but the thing is, they didn't push it until Robb. A big reason for why they chose Robb to be king was that in many ways, Robb was the heir to Ned's legacy. He was just as honorable as Ned, and so when he fucked up by sleeping with Jeyne, he married her. Taking Jeyne as a mistress is even worse. The Freys would still likely be a bit pissed off, and the other Northern lords would see Robb taking on the enemy as a mistress.
And this is the worst way to resolve the problem with Jeyne. We have to remember who Robb was at this point. He is the sworn enemy of House Lannister, and tons of propaganda about how Robb is a beast in human flesh is being spread. For Jeyne to have her virginity taken by such a man makes it pretty much impossible for her to be married off to someone within the Westerlands of even remotely decent social status. Robb though, has now taken the hypothetical fire that is this problem, and dumped gasoline on it. Jeyne is now the King's mistress, and once Robb marries his Frey girl, she has zero marriage chances, and don't even get me started on possible bastards.

Beautiful stuff.

Now that was a beautiful chapter. Warms the heart. Bring on more of the Rob/Ros.

Hmmm... this is certainly a different way to tackle the issue. I look forward to seeing where you take this.

I’ll have to be 100% honest, I skip all Jeyne scenes that don’t involve Rob or Roslin. The idea of the love triangle is presented in the summary but really, Rob was with Jeyne, married Roslin and never went near Jeyne again. That’s no triangle, really. He got over her in about 4 chapters and now we’re just watching her love story for no reason? The was never much conflict between Roslin and Jeyne... No arguments... nothing. Jeyne and her story is boring here for me... she seems like a chapter filler, that’s it.

A great story. Very well done.

If only it was Jeyne in the real GOT that Rob fell in love with... Then he would have, dare I say become king of Westaros

Wow... Lovely concept

oh the end. I am so mad at this two idiots. roslin my poor child does not deserve any of this. The stress on her pregnancy. I really love this fic

oh she is pregnant, and I understand her fears. Robb needs to recognize his love for Roslin. I am so glad jeyne is finally determined to move on, and it is all made organically

Robb needs to be smacked in the back of his head

the evolution of their relationship feels very organic. The pacing is perfect, and the end of the chapter was adorable