Alternate Cheat Method
Go to x:\Program Files\Bullfrog\Theme Park World\data\levels\
and open Online_Standard.sam with Microsoft's notepad.
Note: Before you modify anything backup the file in case you don't like the result.
Then scroll down until you see "Arrival rate stuff". You can modify these 5 settings.
On Arrival.MinPeople I put 100 (be prepared so most of them have something to do at your park and that you have many cleaners)
On Arrival.TimeBetweenArrivals I put 10
On Arrival.FixedRate I put 15
On Arrival.NewParkBonus I put 99
On Arrival.PointsPerVisitor I put 99