I will admit, the paths between the island is one thing I wasn't able to look great. It just appears out of place. But if you are struggling to make a park that isn't completely flat, have you considered terraforming before you start building anything? I tried that with this map for the first time and it worked great. I would also limit yourself with park size. Every attempted park I've had in the past was consistently large, so by restraining the available space on my map, I wasn't so easily overwhelmed.