N traveler, wayfarer, voyager, itinerant, passenger, commuter, tourist, excursionist, explorer, adventurer, mountaineer, hiker, backpacker, Alpine Club, peregrinator, wanderer, rover, straggler, rambler, bird of passage, gadabout, gadling, vagrant, scatterling, landloper, waifs and estrays, wastrel, foundling, loafer, tramp, tramper, vagabond, nomad, Bohemian, gypsy, Arab, Wandering Jew, Hadji, pilgrim, palmer, peripatetic, somnambulist, emigrant, fugitive, refugee, beach comber, booly, globegirdler, globetrotter, vagrant, hobo, night walker, sleep walker, noctambulist, runabout, straphanger, swagman, swagsman, trecker, trekker, zingano, zingaro, runner, courier, Mercury, Iris, Ariel, comet, pedestrian, walker, foot passenger, cyclist, wheelman, rider, horseman, equestrian, cavalier, jockey, roughrider, trainer, breaker, driver, coachman, whip, Jehu, charioteer, postilion, postboy, carter, wagoner, drayman, cabman, cabdriver, voiturier, vetturino, condottiere, engine driver, stoker, fireman, guard, chauffeur, conductor, engineer, gharry-wallah, gari-wala, hackman, syce, truckman, on the road.

For further exploring for "backpacker" in Webster Dictionary Online