In terms of distance: New Delhi to Toronto (..that's like the opposite side of the world)
in terms of time: New Delhi to Kanyakumari (via train took 2 and a half days, one of the best trips I can recall)
Family road trip back in 2005 manglore-banglore-mysore-ooty-coimbatore-madurai-tiruvantpuram-srisailam-kanyakumari-rameshwar-tiruvannamalai-tirupati-bangalore