We're thinking mid to late July if itall works out, but we don't have a specific deadline to leave yet. That may depend upon getting suitable tenants for the house. Like you, the closer it gets the more there seems to do! At this point we've put off the 'Alice to west coast & up to Broome for the wet, with Kimberley exploring for the entire following season' trip off until next year as it's one we really want to take as long as we can doing, & July is later departure than we originally intended.
Instead we are thinking of heading up to Queensland via inland tracks & spending a while exploring channel country until it gets too hot & then going east to the Great Dividing Range, heading back south staying in the mountains all the way. Then maybe Tassie until about March/April followed by the trip up to Alice & across the western deserts & up to Broome getting there around September/October (hopefully find a house sit/somewhere to stay under cover) & then explore the Kimberley in as much detail as we can over the following season from as soon as the roads/tracks open. We reckon that should all take us up to around Sept 2019 by which time we will have had plenty of time to think about where to next. No intention to look for paid work but plans will change if experiential opportunities arise along the way.
We also have a sat phone which costs the same to call as a normal mobile phone & I'll let you know the number once we set it up.
Mate ......... we are so lucky .......... it's gonna be a ball!