After a car crash leaves him unable to walk and dying of thirst, an inventor and his physically-disabled cousin must traverse the harsh Australian desert using only her electric wheelchair.

Don't worry about length at this point.

30 words is ideal but not a must, if the story needs a few more words to come across in the logline, then let it be so unless of course a company or contest specify a 25 word limit.

Other wise I'd endeavor to say you're still writing the script, if so this is a structuring tool for you in which case there is no word count limit.

I think the re drafts of the logline work well.

Perhaps, as DPG suggested, add in a time frame and mention how far out from the nearest town they crashed.

For example:

After his legs are crushed in an accident, 3 days out from the nearest town, an inventor and his physically-disabled cousin must use her electric wheelchair to escape the harsh Australian desert before dying of thirst.

What's the time frame for the story? ?That is, how much time elapses between the inciting incident and the denouement of the ordeal?

The reason I ask is that ?realistically a battery for a wheelchair last could only last for ?several hours ?when operating in rugged conditions where mobile efficiency would be significantly impacted. ?Ditto even more if transporting two bodies. ?Another complication, and a good one .