It's never a good idea to put more feeders in the cham's enclosure than it will eat in a day.
There are a number of reasons:
a) Large numbers of feeders are likely to confuse and stress out the cham (especially younger chams)
b) Crickets left overnight have been known to nibble on chams (I've seen it with my own eyes). On younger chams this can be particularly damaging.
c) Crickets left in a cage for prolonged periods will try to get out by force. They will easily chew through reptariums, plastic and fibreglass mesh. A breeder at a reptile expo recently told me that he even had crickets chewing their way out of fine steel fly screen!
d) Insects left in an enclosure for prolonged periods can die in the enclosure, promoting the growth of bacteria and parasites.
But as for the original question of leaving your cham alone: a couple of days/weekend away can be managed provided your cham has access to water (a looong lasting dripper or automated misting system) and his lights are on automatic timers. Most chams, especially older ones, can go without food for a couple of days.