Just doing the maths:
Took a one hour and 500 ly trip to the station from the bubble using road to riches. Mapped the first five even if they were 2000 ls from the star but it took too long, so mapped only those less than 200 ls from the star for the second part of the trip, still a couple.
In total 33 points and 13 million credits. And my trip might have been more like two hours to be honest, but I did a little extra scanning that took time from the goal.
If 5000 players make one point per minute (ie three minutes to jump and map, or one minute to jump and DSS scan, both of which are insanely optimistic) we gain 300k point per hour. The target of this CG is 27 million, about 100 times more.
Yes, that is an average per player of more than 100 hours, if the turnup is slightly larger than the precious goal out here, where fleet carriers weregoine like shuttles back and forth.
I was top 10% on that one and definitely did not spend more than 50 hours (half that, in reality perhaps 20-30?).
How far from possible is this, in reality?
So far, after 18 hours (given the lack of UC from the start), we have 18300 points (approx). A little shy of the nearly four million per day target. Yes, it will probably increase a bit during the weekend, but who can spend 100 hours playing Elite Dangerous over the weekend?
No way the targets will remain like this, unless we suddenly have an influx of 500 players that want to dump all their cartography data acquired over several months in the black this very week, so that someone else can get the bonus the next week(s).