"Best" is a relative term. There are 4 cable parks in the US. Each one has it's quirks and issues. I've only been to the one in Orlando ( Orlando watersports complex) and it's nice as long as it's not crowded.
Depending upon where you fall, it could either be a short or very long walk back to the starting dock. Normally is isn't that far of a swim back to shore.
Yes, you swim. Usually no more than 50 meters since the cableway is built next to the shoreline. If you think this is bad, it is not, because you are actually resting when you are swimming and walking back to the starting dock.