As a general personal rule if I am outside the circuit I have at least one current paper chart and unless I have Two iPads, I have ERSA as well and please note that these backups must be accessible to the crew, not chucked in the back with the baggage. If you need glasses you must have a spare pair.
I'm not sure that "verbal" evidence of weather weight and balance and fuel logging will get you very far unless you haver perfect memory.
I generally do a quick back of the envelope W & B and If I’m touring I have a "trip book" which has my generic W & B for the tour written in.
Fuel log is just the back of a flight plan form.
However if you get a bloody minded FOI he will find something to ping you for and there is nothing you can do about it.
Its fear of one of these encounters with the capricious CASA that keeps me from attending fly ins, Birdsville races, etc. At least on the road with the police you can argue the point and the rules are pretty much set in concrete and easily applied. CASA? No such luck.