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It's not a simple process to "meg" in reference to your last sentence.
There are many previous threads with replies about this process, that you can easily find use various terms, and with the use of Advanced Search, like lightning, lightning damage, etc.. you get the idea.
I for one would draw a map of the circuits on the house. Be it just simple boxes and devices!
I would also ask for the house to be vacated being the fact that there will be no power during your testing. Frankly you are going to ID everything and touch everything that's plugged in remove it and then replug it in (wich depends on how you write your contract...
I frankly would not depend on a meggar alone, circuit tracers will easy show "tone" to make a drawing fast and help isolate issues on the affected areas...
But
One problem with lightning is that it might rattle a device loose at the screw(s) that might or might not show up.
If my name was out there, I think I would want to touch every device, to know, and that includes everything passed by a meggar!
Anything that gets touched that breaks due to age, or stab-in receptacles,
out of date receptacles, previous broke receptacles, broke receptacles without ground, any odd work found, all should be priced ahead of time, or part of why your looking at the house. Ok let me say it this way if your Q.A. the House then how can U not bring it up to Code. Granted the price might not be covered by insurance but how can you say it's good if broken?
Tough call...
