I'd leave a handful of crickets in the cage.. Some people say not do leave crickets in overnight because they can bite your chameleon, but if your cham is not a baby, I'd say don't worry about that. Let's not forget who's the preditor here
That aside, lighting and misting are HUGE factors.. Do you have an automatic/timing system?? If not, you have an issue. To handle the water, you can put a dripper on top of the cage.. just get a liter, poke a hole or two in the bottom, fill it with water and set it ontop of the cage... Lighting, on the other hand, won't be a fixable issue unless you can have a friend come in and turn the lights on/off for you.
I highly recommend getting a misting system like the MistKing if you don't have it already.. Also get your lights on a timer, that way you won't have to worry about future trips out of town like this one
Quickfix, go to Lowe's, Orchard Supply or wherever and buy a $15 timer.. Connect your lights to it and set them at 10-12 hour intervals.. Do that, setup a dripper like I described above, throw some crickets in the cage and your cham will be perfectly fine
