Writers who plot do the research first, before putting pen to paper, or fingers to keyboard. Definitely an advantage.
Me, I do it after; I'm so easily distracted, it delays the actual writing process because there's so much interesting stuff out there. Sure, it can mean re-writes, but re-writes are a part of producing a book - it's a matter of degree.
So I discovered Brazil is much bigger than I thought. Or should I say, that getting around the countryside is much more difficult than I expected and there are more airports than I expected.
I'll have to be more creative in explaining stuff that I assumed was right from brief readings. For a while there - after the read through and thinking about Brazilian transport - I thought I'd have to virtually delete eighty percent of the novel. Fortunately, I slept on the problem and it's not as bad as I feared.
And what is this near overwhelming problem with transport? The choices of vehicle to get from a major city to a minor one up the Amazon river. By car and ferry, it can take a week or more. But flying? Meh. Nowhere near long enough for a relationship to develop.
More thought is needed...