Speaking as a passenger ... when a light aircraft is staying low and 'hedge hopping' to stay (they hope) unnoticed, the passengers may find themselves wishing they had not had breakfast ... Also, in sub-tropical regions the air density can change very quickly and this leads to bumps and drops, exacerbating the discomfort for the passengers and the risks of not having enough suitable bags in the seat pocket. Pilots of these aircraft are innured to this. I would not want you to be graphic but it adds another facet of realism.
I agree with those who have said: Establish the rules and stick to them! I spent 27 years in telecommunications and IT, so I get highly irritated by the modern films and TV serials that have some junior crapping away on a keyboard and then shouting, "I'm in!". Whilst hacking is 100% possible, please make it look realistic. As a specialist, I am sorely irritated when a style of telephone (fixed or cellular) is chosen because 'it looks right' rather than what was being used in that time and place. I then discount almost everything else they have put in that I do not know about.
It sounds as if you are planning your 'cowboy' to be in the analogue era and thus fewer electronics - which is good! Electronics are used too freely by writers as a get-out-of-jail-free card. If you get your character into trouble then, either they get themselves out the clever way - or they get stumped!