I've heard that the KIPP summit is really useful, but that might just be because my friends in KIPP schools like going to San Antonio or Orlando. For a network like that, though, I imagine the benefits of getting all their teachers together for a conference might outweigh the costs. After all, the most successful networks--like Uncommon and KIPP--spend a ton of time and money on teacher development.
Trips to the Caribbean? Not so much. If that's happening in NY I'm scared to think of what might happen in Louisiana...
Also, what's a "textbook?" Also, what's a "hallway?" I have no experience with these things.