Do yourself a solid and play the game on "Free Play". It'll still pop after completing. You'll have unlimited lives and not have to compete against the clock.
The Swamp is the fourth and final level you'll need to play.
Here's some things you'll slowly figure out, but I'll give you a heads up.
You'll hate the Monkey
Once you hit your first quadruple river hop, there's a monkey that'll periodically ride one of the logs and throw bananas at you. He's awful, but he's not forever. I didn't even bother starting crossing until he passed. Once you're horizontal or past him, he'll stop throwing.
Bullet-fast crocodiles are a blessing a curse
You can surf (exclusively on the back) of crocodiles. Which is rad. Just don't tango with one going mach-3 if you don't have to. Especially if you have the joy of streaming this on PSNow. More often than not, your optimism will be punished and you'll have to start over. This game is not forgiving, sometimes your button-press doesn't register, etc.
Know how many hops are in your safe zone
Every so often I'll think my next hop is into a danger zone, when really I'll have another hop of safety. Know how many hops are in between each crossing area and save yourself the headache of having to realign your strategy after you missed your log.
This is a really long solution to something that just takes a little bit of time. Have fun.