Hi Luke,
I would come with a program that doesn't require kids to have a solid grasp of left or right, or to participate fully in a setting where you're telling them what to do and they do it, to music.
Maybe plan on a lot of singing games, and a lot of you being out there doing it with them - the old classics are great. Warm up with a little Ring Around the Rosie (including the part about the cows in the meadow lying down and sleeping), maybe a little London Bridge in a circle? I get a lot of mileage from the Sleeping Bear song and game, and the one about the small frogs dancing in a ring.
Freeze Dance is great, and the ball of yarn thing is great. How about Can't Jump Josie or Sally Go Round the Sun?
Maybe check out the New England Dancing Masters books for ideas?
You can also make stuff up - Long lines forward and back twice, everyone make a tunnel with their hands and top couple dive under - that sort of thing.
If you need more ideas, let me know - I teach parent-child music classes and we do a lot of playparty stuff, so I have a lot of this stuff at the top of my brain.
Good luck!
Meg