Side Quests

There are a number of excursions that can be built around the town of Aronsburg. The river smugglers are the largest and most ready-made for confrontation. They have regular interaction with the river, docks and warehouses. There is a chance every night of some type of encounter. Obviously, on days before or after a large shipment arrives, there is a greater chance of activity.
The usual process for the smugglers is to put in somewhere the night before the freight is officially unloaded, so any contraband can be smuggled off before the bean counters arrive. For outgoing product, the reverse is true and boats will stop across the river before leaving Aronburg to take on cargo.
Depending on how the DM wishes to play this out, the party can stumble across the activity, or the town leaders could enlist their aid as an outside interest to investigate, or the shopkeepers might grumble about "shady dealings" loud and often enough to arouse the characters' interest.
With multiple groups involved in smuggling and raiding, the DM also has a variety of choices of where to take the encounter. They can chase waterborne bandits operating across the river, or chase lizard folk gangs through the swamp.
I had other ideas of side treks when I sat down to type this, but after getting interrupted for an hour and trying to come back to it, I've got nothing. To be honest, sitting back down to type I can barely keep my eyes open, and I'm losing my train of thought in mid-sentence. Time to call it a night and revisit this after a night's sleep...