Where does Leslie want to go with Jess and his family in Bridge to Terabithia by Katherine Paterson?

Leslie wants to go to church with Jess and his family. 

Jess's family does not go to church often. Chapter eight tells readers that the Aarons family only attends church on Easter, and it is a big deal. It is an especially big deal for Brenda and Ellie because they are excited to show off new clothes. It's obvious they are missing the point of church.  

Jess is not thrilled to go to church. He claims he never gets much out of going to church, which is why Leslie's request to join his family surprises him so much. Jess can't fathom a reason why Leslie would want to go to church. 

He went back to work. "You'd hate it."

"Why?"

"It's boring."

Leslie does indeed end up joining the Aaron family for the Easter Sunday service, and she loves it. She finds everything about the service fascinating, and she sees the story of Jesus's sacrifice as storybook beautiful.  

"All those people wanting to kill him when he hadn't done anything to hurt them." She hesitated. "It's really kind of a beautiful story — like Abraham Lincoln or Socrates — or Aslan."