Re map apps. I have been using 'Memory Map'
for Off-line topo /street and HEMA maps on my PC plus on the phone/tablet for a while now. Works good in Australia, and in NZ and the UK from experience. On Andriod app is free plus base 1:250,000
map of Australia can be downloaded free also. On Apple I think you have to pay a small fee.
Young ones need to understand that such apps work with off-line maps loaded in advance onto your phone and don't need a data connection to operate - sort of essential in rural Australia. package will give GPS read-out, tracking etc.
From experience many Sat phones have a feature that will simply send current GPS data as a text.