When Dwight decides to buy gifts for his family, he gets the bright idea to buy his daughter a shiny new pogo stick. Turns out that pogo sticks are a lot harder to find than you might think. Hey, it's the end of the world; do you think the pogo-stick factories, of all things, are still up and running? Anyway, because of this difficulty, Dwight's quest for pogo nirvana eventually blooms to Gollum-like proportions.
First, we should note that Dwight's daughter Helen—along with the rest of his family—met their ends during World War III. That doesn't stop Dwight from acting like they're still alive, though. He eventually decides to buy each of them a gift, though that precious pogo stick remains elusive even after an exhaustive search. This leads to a classic catch-22: the harder Dwight looks, "the more it seemed to him that a Pogo stick was what he really wanted, and that nothing else would do" (6.194).
But wait just a nostrilpickin' minute. Can you remember where Dwight got the pogo stick idea in the first place? That's right—it happened when he stumbled across Moira's childhood pogo stick while he was poking around her garage. At that point, he happily declared that "it's kind of fun, looking at other people's toys and trying to think what they must have looked like at that age" (4.306).
This makes us think that something else is going on—that the pogo stick represents innocence (and, specifically, the innocence of childhood) to Dwight. We don't know about you, but we'd imagine that the thought of innocent childhood times would be quite comforting in a post-apocalyptic, soon-to-be wasteland.