Halloween campground dance, huh? That was my old market for many years. Didn't pay worth a damn but it was fun.
Back when we were working the market we'd arrive early, in time for the trick-or-treating. We overnighted at the campground so that helped. Hand out candy and glow bracelets and tell 'em there will be more at the dance... but they've got to be in costume.
This is where your wireless mic will shine. The costume contest is just a part of the overall fun. Many campers decorate their sites so be prepared for a site decoration contest as well. Your audience is the judge, of course. The managers will have to be on board for the site judging. They know who's who. One campground we worked for, the manager's missus coordinated all the contests and did the MCing. That made my job a lot easier.
If the pups are into punkin' decorating or carving, their works can be displayed around the dance area. Do the Limbo, the Train, any line dance the pups like to do and have the audience judge by applause. First and second prizes can be inexpensive gadgets ~ the last one we did, we gave away little calculator pens.
Just my experience ~ mix it up and hold off on the site judging 'til later. You'll want to keep the crowd there. We've seen 'em leave after the announcements. Don't do 'em to soon.
Whatever ya do, ensure that every pup gets some sort of prize, even if it's a glow necklace. Reason I say this, it's Halloween and Halloween is when every pup gets treats.
Thoughts?