My child gets very excited and overwhelmed when in large groups. She loves Halloween and costumes, and she loves rescue vehicles (as long as the sirens aren't on). A large car dealership in our area had a "Trunk or Treat." It was huge.
1. Asked questions to understand better
2. Listened thoughtfully to the answers
3. Found someone he personally knew who would be cool
4. Spoke to him privately about it
5. Respected my daughter's needs
7. Pointed to the refill table (where the megastash of candy was off to the side to refill the trunks when they were low) for my daughter to have a place to trick-or-treat that wasn't too crowded