Hi Gordon! Well, during my holydays I did carry a few non-photographic things like small souvenirs, my asthma spray, town maps, etc, but not much else…
As for bigger things as those you mention, yes, you can certainly carry them; in the upper compartment for example there's plenty enough place for a can of soda or a small bottle of water along with a sandwich or two (this compartment is much smaller in the 100 AW).
I didn’t have any sandwiches at hand (sigh) so I had to improvise, here you can see a couple of shots of the upper compartment with two standard 33cc cans of soda (no harm intended to other brands of beverages out there, I just got those two at hand at he moment…
You can see they fit in quite nicely; you can even squeeze a third can horizontally in front of those two, or perhaps a few small snacks (such as chocolate bars, peanuts…).
Well, I think that’s about it for the upper compartment.
As for the main compartment, it depends of course on the number of photographic items one owns or wants to carry along. Chances are that, when going to out to visit some town or walking the country, one will carry just the body with a lens attached and, at most, an extra lens and a flashgun (along with other small things like a spare battery or an extra memory card). Provided one doesn’t push the number of items much further, there’ll be left a very respectable amount of free space in the main compartment which, by the way, is very customizable.
Here’s a shot of the main compartment empty, beside you can see my D40 with the 55-200 VR attached, the 18-55mm nicely stored in a pouch, two cans of soda and the padded walls removed for the occasion:
Here you can see a shot of the main compartment filled with the body, the extra lens and the cans of soda, note that the space occupied by the beverages have an empty “twin” (they are almost exactly the same size) in which you can easily fit up to three sandwiches:
So, if the question is if you can carry your gear in this bag along with some refreshments to keep you going during a long walk, then the answers is definitively yes. Besides, while the bag is not intended to be isothermal, my guess is that the thick padded walls can keep beverages chill for quite a while.
As for a spare battery and/or memory card, there’s plenty enough space for that in the front pocket.
Of course, the moment you put your hands in this bag you know what it was designed for and that is to carry photographic gear, so one can't expect miracles (forget about magazines, large bottles, etc), but I think you can hardly ask such a thing of a backpack of this size, there are lots of bulkier bags out there designed for those purposes…
Hope I’ve helped.