Originally Posted by
mulveyr
I would, and have done so.
Campgrounds are far from hotbeds of thievery ( yes, I know someone will feel obligated to come up with a "Yeah, but I had X stolen from my tent..." story ), so it's highly unlikely you'd have to worry about it.
The alternative is to go to reception and ask nicely if they can take care of the valuables for you while you are off doing something in town. Ensure they take your bag of stuff over the counter and note where they put it.
But generally, if that sort of service isn't available, I take those valuables -- camera, computer and documents -- with me in a small backpack (Sea to Summit that packs into its own bag to less than the size of a teacup).