Well with 16-ish? suburban train lines and the world's longest tram network, there's no way anyone could cover it all in just four days. In reality, there's even less time available to Mojo as peak times are packed and travelling is no fun at all
So perhaps we should suggest which routes Mojo should try? For a start, I'd suggest:Trams.No 8.
Toorak to Moreland. The route from the city to Toorak heads down St Kilda Road before heading off down scenic Domain Road to Toorak Road which it follows through hectic South Yarra and leafy Toorak. The northern section from the city through affluent North Carlton. hipster Brunswick to ethic Coburg sounds interesting, but it isn't. So I suggest that you just do the southern bit from the city to Toorak.No. 35.
City Circle. A route with elderly W class trams that commuters loathe, but which tourists seem to like. There is a truly awful recorded commentary that makes me cringe, but you do get to see some of the sights as well as venture into the concrete canyons of Docklands in (relative) safety.No. 55.
Domain to West Coburg. The bit through Royal Park is rather scenic.No. 96.
St Kilda Beach to East Brunswick. The northern part is pretty nondescript, but the section from the Royal Exhibition Building through the city down the former train line to dodgy Fitzroy St in St Kilda, along the scenic Esplanade, past Lune Park to Acland St is one of the best tram routes for a tourist.No. 109.
Port Melbourne to Box Hill. Follows the route of Australia's first railway line from Port Melbourne to the city. From the city it heads down scenic Victoria Parade, along ethnic Victoria St, through affluent suburbs to terminate in the overwhelmingly Chinese suburb of Box Hill.Trains.
Much of suburbia is fairly generic, but once you get beyond the inner suburbs, the sections worth seeing are:Belgrave line.
Upper Fern Tree Gully to the terminus. This has the bonus of seven day a week narrow gauge steam trains 200 metres away.Hurstbridge line,
especially the part past Eltham which is semi rural and features a winding single track with wooden trestle bridges.Williamstown line.
A short spur line to the only really wealthy suburb in the west. A scenic peninsula with attractive buildings surrounded by water on three sides. Nelson Place is a good place to grab lunch.