Hills ain’t too bad.
Anything you have to crank up you eventually get to speed down. There might be a view at the top.
Wind is something else.
Of the small things that make a difference for someone on a bicycle the wind direction is high on the list. Travel with the wind behind you and the miles just tick off. Smash into it and be battered both physically and psychologically.
The prevailing winds, mostly seasonal, are somewhat predictable which suggests that selecting the best start location and pedal direction will be amply rewarded.
Heading north from Adelaide to Darwin in autumn, tick.
Perth to Sydney in the cooler months, ditto. The prevailing wind is south west and it can be fearsome with no vegetation for protection. Sydney to Perth when warmer is OK, just not when it is excessively warm, like January.
OK, you can be unlucky and spend a few days battling away.
Check out the wind roses from the Bureau of Meteorology, BoM, for the different months or seasons for either morning, 9am or afternoon, 3pm.
Or, to see what is happening with the wind, right now, this moment, there’s always this fantastic pictorial graphic for the wind.