When the boys are asked where the girls are: Randy responds "They're picking kelp out of their ears". Kelp is a saltwater plant. Plants in the Great Lakes are typically referred to as sea weeds (even though they're not in the ocean) or just plants, but never kelp.
Just because a barbecue is lit that doesn't mean it's ready to go. No matter the fuel it still takes time for all the coals to get hot enough for cooking.
When the kids are in sitting in the boat you can see one of the camera guys on the far left corner holding the camera pointed at the kids on the boat, as Tim & Jill come speeding past them knocking them over into the water. Also you can spot a camera on the front of the boat that Tim & Jill are in resting on it's mount.
With lodge not being open there'd be no one there to rent out the cabins.