Hi Don,
Gary here. As mentioned, what the rental companies tend to do is offer the GPS
unit as a standalone 'tick in the box' option. If you request the option, sometimes
the check-in person will hand you the unit at the counter in a little bag and
you affix it to the dash or window and stow it in the glove compartment when not
in use.
I used one from Budget in California last month and what was impressive
was the live traffic data feature where it warns you of congestion and can then
attempt to re-route you. To the best of my knowledge, I don't know of that service
being available here yet in Australia - not that you will need it on your trip -
but in the greater LA area where I was using it, the first time it said
"Congestion ahead. An alternate route is available", it took me by surprise that
the unit had that feature and sure enough, she was right and assisted me in avoiding
the delay.
If I can assist in any way for your trip, drop me an email at
sales@wildcard-innovations.com.au
Looking foward to seeing you again soon!
Best regards
Gary Kopff
Mt. Kuring-Gai