On the drive or fly from Sydney to Melbourne question -
It takes maybe 10-12 hours to drive including stops, mostly on a divided highway similar to US Interstates, or 1:15 flying time, plus an hour to get to the airport, plus checkin an hour before takeoff, plus 30 mins to get your bags, plus up to an hour to get into the city (including waiting time) = nearly 5 hours of moderately stressful time. All you see is the road to and from the airport, and the inside of 2 airport terminals. However, some people, including me, like the process of flying or taking long distance trains.
Some posters here will say that the drive is boring - well, to them it is because the landscape is familiar to them. To a visitor who's 'not from here' it would be all new and therefore an interesting drive, particularly if they divert off the freeway into some of the small towns along the way (I suggest Goulburn, Gundagai, Holbrook, Wangaratta, Benalla, Violet Town). For someone who is not familiar with driving on the left side of the road in a right hand drive car it might be moderately stressful. Canberra might be as boring as Ottawa (but I have not been to Ottawa so cant comment) but on a fine day it is beautiful to look at, particularly around the lake, has some magnificent public buildings (suggest Parliament House, National Gallery, War Memorial - for an insight on what's important to Aussies) and plenty of good eating places. There is a good wildlife park there too. Canberra deserves at least one whole day if you decide to go there.
I'll leave comments on the other aspects of the OP to others - they've covered it pretty well.