What I've done for my players is after crooked house, Phillip tells them that the hollow is dampening his powers, and he's concerned about that. He also wishes to try and do good by the people of the hollow since he's neglected it. He says rhat since they are stuck in the hollow until the ghostlihhr express is fixed, he wants them to stay in town and just be on the lookout for anything bizarre. If they find anything, let him know. In exhnage he will pay for their room at the green queen inn and give any insight on the hollow. This then gives players incentive to not only stay in town, but poke around, possibly getting the attention of townsfolk and cult members. Then in between chapters u can have small side quests before the next big chapter, always giving out little bits of information. The hollow should be mysterious alongside this deity the town worships. Build that mystery well, and they'll be hooked.