Veronica could be Dorothy
Margie could be the good witch and the wicked witch (she has shown tendency towards both)
Challenger could be the Scarecrow (after all he was the brains behind the whole adventure)
Roxton could be the TinMan (he can certainly steal a few hearts)
Malone could be the Lion (always counted on to help a friend but doesn't blindly rush into danger -- notice he didn't have to ask the Wizard for a brain!)
Summerlee could be the Wizard (always despensing pearls of wisdom)

Veronica could get bumped on the head falling down a well. She could imagine herself transported into London. The whole episode could revolve around her trying to get back home to the plateau.