Board Thread:Unanswered Questions/@comment-25069258-20150214230334/@comment-1824272-20150214231025

This is an absolutely terrible idea. You can't get more than 2,500 points in Free Mission unless you hack the game, and if we assume that you already have accumulated 500,000 points, you would need to earn 2,500 points 200 times. And don't think that you'll always get 2,500 points in a Free Mission, because even reaching 2,000 can be difficult sometimes.

Online is honestly the best way to farm this. Get a friend and farm out the points. I can help out, because I also want to get all of the achievements, one of which requires those 50 hours of online gameplay.