Insert disk 3 to load the game without the intro sequence, as the screen goes blank press 'C' a few times. Once the game has loaded, select a new game, then when you get to the map screen you should notice that your player's name has changed to "It's You, Buddy". Now when the game starts, you will have plenty of cash in your bank account.
Enter "FLIGHT SIM" for the name of the park and you will start the game with 200K instead of the usuall 130K.
Enter "DEMO" for the name of the park for a ready made one.
Position a bouncy castle anywhere in the park (positioning the entrance and exit any where). Now pause the game until you notice the writing above the entrance speed up, and type 'L', (pause), 'I', (pause), 'V', (pause), 'E', (pause), 'C', (pause), 'A', (pause), 'S', (pause), 'H', (pause), 'P', and 'P'. You should now get a new shop and ride every year.
To get the baddest roller coaster without having to pay for it, place your roller coaster doorway where you want and build the smallest loop you can around it using the least number of sections possible. Open it up and close it down immediately (to only be charged for the tiny ride). Now remove the tiny loop and build your dream coaster without paying a dime.