"Close, very close. But not quite." He then shrugged. "Space coffee."
He drank and carefully listened to Ellie's tale, nodding here and there when she described something familiar. "I traveled down Route 66 a couple of times, since it's such an iconic thing to do, by Earth standards." This was before Clara's time, when the Ponds were his traveling companions. "So many weird and unusual things along the way. It was like visiting a different planet within a planet."
Clara's ruse seemed to work, because the Doctor was satisfied with her explanation, and pleased to hear that they shared a similar wanderlust spirit.