Walder Frey during the Rebellion

[Angel Eyes]

Why didn’t Walder Frey try to extract a toll (I.e. a marriage) from the Northern forces when they traveled south during Robert’s Rebellion? Was Ned’s arranged marriage to Catelyn Tull already in place? Did the Northern lords manage to get around the Twins without needing to extract a toll? Or did the Northern lords pay a toll we don’t know about (a Frey marrying into the North)?

[Giant Ice Spider]

It's possible they never crossed the Twins at all.

Robb crosses the Twins because he wants to free his father as quickly as possible. If Ned hadn't yet heard about Stoney Sept and the situation Robert was in (which would make sense if he and his host were still isolated in the Neck), then he may not have seen the need to hurry.

To be honest, I'm not even sure if Martin considered this. It seems like such a glaring issue with RR to me.

[Loose Bolt]

During Wo5K Tullys were already weak, Arryns were neutral and main enemy of Starks much closer than during the rebellion. Or Freys could get much better price for their support. In fact trying to make a deal with Ned that he could not refuse could have backfired. In fact during the rebellion "the alliance" could win the war without Freys. So they could simply ignore Twins.

[Bernie Mac]

There is no Crown army at the Trident, Robb wanted to avoid Tywin's host while at the same time was in a rush to get to Riverrun. Completely different scenario. 

 

I'd also guess that Ned was first meeting up with Jon's host leaving the Vale, they likely purposefully went down the Kings Road so they could secure and control this territory against the Crown. 

[Stormking902]

The kings road doesnt cross the Freys bridge, Robb needed to cross the bridge because its the fastest way to Riverrunn which at the time was under siege by Lannister forces and he needed to relieve his uncle Edmure and gather Riverland forces and march on the capital with great haste. 

[300 H&H Magnum]

5 hours ago, Angel Eyes said:

Why didn’t Walder Frey try to extract a toll (I.e. a marriage) from the Northern forces when they traveled south during Robert’s Rebellion? Was Ned’s arranged marriage to Catelyn Tull already in place? Did the Northern lords manage to get around the Twins without needing to extract a toll? Or did the Northern lords pay a toll we don’t know about (a Frey marrying into the North)?

 

4 hours ago, Giant Ice Spider said:

It's possible they never crossed the Twins at all.

Robb crosses the Twins because he wants to free his father as quickly as possible. If Ned hadn't yet heard about Stoney Sept and the situation Robert was in (which would make sense if he and his host were still isolated in the Neck), then he may not have seen the need to hurry.

To be honest, I'm not even sure if Martin considered this. It seems like such a glaring issue with RR to me.

Spider is right on this.  Most of the rebels were already in the south and had no need to cross the twins.  Having that many boots in the south meant Walder could not block the north even if he wanted to.  He would be attacked from both sides.  I would like to think Walder Frey was honorable enough to think twice before betraying King Aerys whom he swore loyalty to.  

Looking at history could help explain why Lord Walder sided with Robb in the first place.  Robert succeeded in his rebellion for the most part, though I am of the opinion that Viserys was the legal king of Westeros.  This had to cross Walder's mind while weighing Robb's chances.  What he did is the same as what Borell did for Davos in Dance.  The Crossing is unlike Godric's territory, Walder can't say "if you lose you were never here" to Robb Stark.  Walder had to decide one way or the other.  If Robert won why not Robb?  He rolled the dice and it was looking good until Robb broke his sworn oath and betrayed him.  Walder still got the better of Robb and the Starks.  Which is to say it was a good gamble for the Lord Of The Crossing and it paid off even if not the way he had wanted it.  You take what blessing you can get and Robb Stark gave him a good reason.

[John Suburbs]

4 hours ago, Giant Ice Spider said:

It's possible they never crossed the Twins at all.

Robb crosses the Twins because he wants to free his father as quickly as possible. If Ned hadn't yet heard about Stoney Sept and the situation Robert was in (which would make sense if he and his host were still isolated in the Neck), then he may not have seen the need to hurry.

To be honest, I'm not even sure if Martin considered this. It seems like such a glaring issue with RR to me.

Actually, Robb needed to cross at the Twins in order to lift the siege at Riverrun before Tywin can get there. That's also why he sent Roose down the kings road -- to draw Tywin north and delay his advance to the west.

If Ned was aiming the Stony Sept during RR, it makes more sense to head straight down the kings road, reconnoiter with the Arryn army, cross at the crossroads, and then it's a straight shot overland to the southwest. If he crossed at the Twins, he would still have to wend his way through the marshes at the head of the Blue Fork, then cross the Red Fork, and then due south to SS. A much more difficult march.

[Giant Ice Spider]

14 hours ago, John Suburbs said:

Actually, Robb needed to cross at the Twins in order to lift the siege at Riverrun before Tywin can get there. That's also why he sent Roose down the kings road -- to draw Tywin north and delay his advance to the west.

If Ned was aiming the Stony Sept during RR, it makes more sense to head straight down the kings road, reconnoiter with the Arryn army, cross at the crossroads, and then it's a straight shot overland to the southwest. If he crossed at the Twins, he would still have to wend his way through the marshes at the head of the Blue Fork, then cross the Red Fork, and then due south to SS. A much more difficult march.

Thanks, that explains it.