What I've always done is if you see a park you like take down the name of the person and DL all their parks. (just search their name in the parks section). I also do random downloads skimming the parks section in game hunting for that one guy no one knows yet but builds sick sh**.

Ladd's got a good point, right now I can only upload 2 more parks so every time I go to upload I have to decide which older one to delete.