There is a phrase called "bring a plate", which means precisely that
to Australians, but someone has already asked me what should be on the
plate, and oddly, they aren't even on the spectrum.  (!)

Perhaps they have just been hanging around with us too long.

Also, bring whatever else you feel you need be comfortable (and that's
also portable).  There's a Milk Bar up the road, but it's a long walk
to the nearest Coles.