They can provide weapons, though not reliably enchanted ones (all the Imperial weapons need mages to charge them), and her choice of longbows suited for the draw of a very strong man, all of which she needs to be careful not to break like a twig.
And she can get stories. So many stories. The precise details are somewhat confused, but - the king gathered his armies and went north, and then they surrendered and were ordered to disband except a picked few who would take up service with the Empire, and most of those didn't show up. So when their officers started to get word from the Central Directory that they were recruiting - well, 'Marshal Orestan' was an assumed name, but there were generals under him who they knew and respected and lords, and Ithik was backing him and he could pay -
- And meanwhile Imperial troops were burning every shrine in the country and it was, really, a very simple decision. Most of them were in camps west or south of the border in the bitter ground there, and others were training in Ithik, but you had raiders who were in the forests of Oris raiding and trying to pick off isolated patrols and they don't really know how the coordination was that good, but Orestan pulled it off, they were almost never caught and nobody knew where they were except him...
... And there were a few little bands caught and mostly they knew was that Old Emerald-Eyes was in charge, the dragon on their flag, and the Empire thought it was just little bands and they had to split up their troops to question every village, had to scatter them through the entire province, and when they heard there was a really big band that was desperately fleeing west the biggest army in the south half of Oris assembled everything it could and crossed the mountains to smash them before they could get away, and Old Emerald-Eyes was waiting for them with an army he'd assembled the day before and when the Empire came down out of a pass in marching order they smashed them and fed off the imperial supply train while they marched east; when they made it to Mahauna the imperial armies had already abandoned it, trying to link up with their allies, and now they're going east to beat another imperial army and they can do that, too.
(Everyone has a fantastically high opinion of the Marshal. Most people figure he's the rightful prince-in-exile; that sounds like a reasonable origin story for someone like him. How exactly he manages to get everything done is really not clear, other than that he's a really good Mindspeaker with a fantastically long range, and uses that for coordinating at distances too long to manage. He maintains discipline but manages to do it without looking like a monster, and is some kind of logistical genius, and... honestly basically every other good trait that can be found to praise in a general. There may be a bit of halo effect going on, here.)