Never even been to Australia lol, just preconceptions. I've been to California and the North-East of the USA including New York. I would personally much rather do this. As for scenery, a quick glance at a map of the US shows me you could quite easily take in NYC, Niagara Falls/Canadian Border, beautiful New England countryside, Philadelphia, Washington DC, the Appalachian mountains, the Deep South (maybe Tennessee, Arkansas), some Texan cities, deserts of the South-West including Hoover Dam, Grand Canyon, Las Vegas, Yosemite National Park, a coastal Californian town (e.g Santa Cruz) and then SF. Having been to both, I can tell you San Francisco is a much nicer city than Los Angeles.
You could take a more Northerly route instead, and go via the Great Lakes, Niagra, some of the industrial cities maybe (Detroit, Cleveland), Chicago, South to St. Louis or Kansas City then across the Great Plans (which are supposed to be pretty boring), to somewhere like Colorado where there are mountains etc, then across Utah and Nevada, possibly including Las Vegas and Californian sights such as Yosemite.
I've been thinking about this way too hard!