Back and forth implies repetitive motion, like 'rocking back and forth' or, more than one trip between two points. Not really the same as just 'there and back' in English but, both answers are accepted for oda és vissza here. Is it really used both those ways? Also, would this be the correct subtitle for The Hobbit (or There and Back Again) ;)
You can say for example Oda-vissza utazunk (we are travelling there and back). If you're talking about a ticket and you need an adjective, I think you'll most likely hear/use retúr jegy (sounds more colloquial to me) or menettérti jegy (sounds a little more official, like what might be printed on the ticket).