Much, much easier if you do it with the multiplier red bricks, and when you've completed all story levels.
2x
4x
6x
8x
10x
= 3480 times each stud value.
Red Brick Locations video - NOT MINE
Now when you have completed the story (recommended), go back to levels to go for the true survivor accolade on all levels, and buy each multiplier brick from the Visitor Centre as early as possible.
Now when you have 2, 4 and 6 activated, it gets easy to reach 65 million, as a 48x multiplier on the Tyranosaurus chase bonus level should net you 12 million studs for roughly 45 seconds it takes to complete the level.
Go and collect/buy the 8x and 10x bricks with this, (4 mil & 5 mil) and replay this level again to easily surpass 65 million and the achievement will pop during the level.