Change the date not too long from the real time ( say that it is 8:40. I will change the date to maybe 9:40.) Collect the money, do that again as much as you like, but not too far. ( I change the date to 2035.) don't do that! It'll ruin the game and start all over.
If you get 2 or more mystery trees,when they are fully grown put them close 2gether and when you use snoopy on the skateboard 2collect, he goes super fast back n forth (like a glitch) n collects so many you can easily move up 2 levels a day and the star never goes from above the tree.