Well, I've gotten all the extra upgrades, every booth, and 100 guards. The 15 saboteur in one day is never going to be completed since I never get 15, infact I've been trying for 200 ingame days, so let's just say I'm done with the game. I'm on day 363. Yeah, I should stop, but I'm loving this game.
Here's what I do sometimes: When I'm about to leave, I get my mall in a point where it'll be just fine without me, set the speed to 3x, then leave. Although I come back and 50 or 100 days has passed ingame, I have a huge plethora of money, which then I feel like $_$ and help the mall a lot with all those G's.
Make sure you take breaks to eat, sleep, and use the bathroom. Other than that, MUAHAHAHAHAHAHA