Sorry for being thick but I am not experienced in theme park. once you have attained tycoon status, what do you do? Do you just move on to the next theme or keep adjusting the park you have etc.
As T.j. pointed out to you it is indeed entirely up to you.
However, being a long-time RTC fanatic I can tell you you are on the right track...
Option #1 - Continue building and playing on your Chosen Park you are on in Career Mode.
Option #2 - Start a New Park Mission in Career Mode. Each of these has 3 skill levels to complete.
Option #3 - Alternatively, there's the Unlimited Sandbox Mode if you want to build with Unlimited Funds. The downside to this is that you won't have anything to earn and just do building and maintaining while watching over your park pretty much. If you don't want that then your best bet is just to go back to a Mission Park and either go to the next one on the list or continue from an existing one.