Henry wrote "I'm just a dumb old f#rt but my recommendation would be to use the existing infrastructure.
Get a really low price tablet and hook into the free wifi provided at coffee shops on most High Streets. That way you have no technology problems and don't have anything of value to be stolen"
That is one option, but I need more consistency and guaranteed availability even when away from wifi locations.
Eg when travelling in a taxi, driving in a hire car or at the aircraft in the middle of the ramp at an airport away from any form of wifi.