Cain's small team sets out right after the goodbyes are said, while the rest of the Guilds are still socializing and getting to know their teammates. Without any credible leads of Ogres in the area they're in no big rush, and it's more important to them to balance members skills for optimal group efficiency than to rush out in a blind search for something to kill.
The Quest they were given was to stabilize the region around the Troll capital, and it looks like that is already mostly done. Once they clear out a few more occupied villages they'll most likely get the quest achievement.
The forests and swamps of the Troll Kingdom are unusually quiet, any wild animals either hiding, or hunted to extinction by ravenous Ogre armies. The war went on for years, and this region wasn't ever capable of supporting so many.
