We all know the ideas about the "ideal zombie shelter" stocked with food, water, and ridiculous amounts of ammunition, hidden somewhere up in the Rocky mountains far from cities. But what about Suburbia? What items that one could reasonably expect to be in an upper-middle-class home would be most helpful in a zombie apocalypse scenario?
For this, assume zombies in the World War Z vein (spread virus by biting, not overly intelligent, but decently fast). Our family lives in White Picket Fence House #31 in The Suburbs. At 6 pm one evening, the news reports the apocalypse is starting, although not yet in full swing. The family of four (two teenage kids) have an hour to grab everything they can cram into their minivan before hightailing it to Grandpa's cabin in the mountains, about an eight hour drive away. What do they grab? (Additionally, is there anything they might not have but would be worth the ten minute drive to the local hardware store to obtain? Society hasn't completely broken down yet, so the roads/stores are somewhat usable for the next 12 to 16 hours.)
Note: it's reasonable to expect that they might have some sort of prep, especially given that we seem to be living in the end of the world already. But this isn't a military family, and the extent of their specific prep for disaster AT MOST would likely be a mediocre "bug out bag", and probably a couple of firearms.
Edit: I am primarily looking for what sort of "normal" household items would be useful.