I agree with Austastar, rathing than pick how long your driving hours are pick a start time within 1/2 an hour give or take say 7.30 to 8.00am and pick a good time to stop and camp, say 3.30 to 4.30pm and pick some places to look at along the way, this is not a regiment though, you may find you stop before that, especially if you find somewhere you'd like to explore a bit more.
Have a plan, but allow yourselves to be flexable with that plan, find places that interest you both on your route, as an excample we used the up by 6.30am for a 7.30am leave, that included looking at what was of interest along our planned route to our next stop, with that in mind off we went, what we found was, the places we had planned for a 2 day we only stopped overnight and some of the 1 night stops we stayed 2 and even 3 nights, our only criteria we stuck to was to be at camp and setup before dark, I would call us mature travellers and this worked really well for us and as someone else mentioned, it's amazing the conversations we had along the way, we talked alot more than we did at home and yes we had alone time too, an iPod with each others favourite music on it is the only other entertainment we had with us, well apart from doing crosswords together sitting around camp, trashy mags are great for crosswords.
We are off on a 65 day trip up to the Kimberley in July and will use this method for this trip as we always do, I can't wait, neither can Kerry, anyway hope this helps.
Baz.
