Yes there is a cheat for increasing your park rating!!!! it is:

Andrew Gillett
just got it, never tested it though....if anyone wants to test it than tell me the results.

Thanks

Yeah, no problem, you can probably count on me for any cheats...I no all of the top-notch cheats...unless they don't exist....(or i can't find them:lol but I could probably get a lot of cheats....

Is there a cheat code which you change the hours for the park, and also change the weather for the scenario?