They end up deciding to play things safe on the return trip; although they don't encounter any Chelish patrols, there are enough signs of increased patrol activity to make it obviously foolhardy to try any of their more ambitious ideas. They continue to periodically encounter wildlife, but nothing so dangerous that they can't handle it. The border crossing itself is fairly straightforward: a Fly and Invisibility hides most of the group, and Reduce Person lets them fit the last two into a Bag of Holding.
Once they're across the border, they start travelling mostly by road; absolutely no one attempts to demand a travel pass from them. They pass through several farming villages on the way to Augustana; it's hard to be sure, of course, but the people there mostly seem happier than in Cheliax, and certainly less scared. There are temples to Erastil and Pharasma, temples to half a dozen gods at once not one of which is Asmodeus, Desnan shrines on the side of the road, an inn with Cayden Caylean's symbol displayed on the sign, laypeople wearing Sarenrae's ankh or Shelyn's songbird or Milani's rose. At one point they meet an entire adventuring party full of halflings, not one of whom seems remotely concerned that anyone will try to enslave them.
The Eagle Knights seem more relaxed on this side of the border, too. They finally introduce themselves with their actual names, and start sharing stories about some of their friends. Elettra teaches Fernando and Mateo some new songs; her favorite is the one about a hunter using his incredible skill at archery to resist a tyrannical new lord, but there's one about a group of pirates trying to escape a sinking ship that she thinks Mateo might like.
Eventually, they reach the outskirts of Augustana. Its towering hills are visible from above the city walls, and even from this distance they can make out the sight of Fort Constance. The road they're on seems to have grown much wider, and they've been joined by too many fellow-travelers to count — most of them farmers, of course, but also a pair of travelling minstrels carrying some sort of instrument resembling a more complex lute, a wealthy-but-barefoot halfling riding a boar, a group of children arguing about which roadside landmark to race each other to next, a gnome carrying a bizarre metal contraption on a Floating Disk, a man who's set up a small cart by the side of the road selling skewers of mutton...