I'm going to cover a concert early June inside a bath house. I've visited the location and it's both quite hot and humid. The plan is to bring in at least three video cameras and have them running constantly for an hour or so (there will be a Panasonic GH2, a Canon HF10, and probably some fairly cheap sony video camera). I will also use a couple of self-powered michrophones (such as the zoom H1).
External power is of course something I will have to abandon, but are there any other tips what I should think of to keep this event safe and high-quality? What kind of problems can I expect to run into?