As long as you feed them pretty close to when you leave and leave a shallow dish (deep enough that it won't evaporate in that amount of time but shallow enough so that they won't drown) of water out for them they should be more than fine. We load up ours w/crickets either the day of or the day before we leave before a vacation, someone comes in to give them water, and they've been fine for three weeks.
Also, we rarely spray ours. They always come down for a drink from the dish.