WordNet (r) 3.0 (2006):

runabout
    n 1: an open automobile having a front seat and a rumble seat
         [syn: roadster, runabout, two-seater]

Moby Thesaurus II by Grady Ward, 1.0:

32 Moby Thesaurus words for "runabout":
   Ahasuerus, Ancient Mariner, Argonaut, Flying Dutchman, Goliard,
   Odysseus, Oisin, Ossian, Ulysses, bird of passage, drifter,
   floater, gad, gadabout, go-about, itinerant, mover, peregrinator,
   peregrine, peripatetic, rambler, roamer, rolling stone, rover,
   straggler, stroller, strolling player, troubadour, visitant,
   wanderer, wandering minstrel, wandering scholar