There are two main entrances to the park, both on the same road, Entrance 1 (44.904853, 15.611739) which is further up north and nearer to the lower lakes, and Entrance 2 (44.882368, 15.618324) which is nearer to the upper lakes.
If you are planning to do the park in 1 day, head to Entrance 1 and park at the parking lot there which is nearest to the lower lakes. From here, take the shuttle all the way to the last stop (St3) which drops you off above the upper lakes at Prošćansko Lake. There are three stops within the park (St1 – Near Entrance 1, St2 – near Entrance 2, and St3 at Prošćansko Lake). From here if you follow the signs for either Route C, Route E or Route H you’ll work your way down towards the lower lakes seeing all the main sites. We did Route H which was the most comprehensive, we took our time and it only took us about 4 or 5 hours to walk the entire park. It was not the least bit strenuous as the hike is mostly well developed paths and wooden bridges over water. Most of it is flat, and since you started at the upper lakes and are working your way down, the entire hike is downhill for the most part.
Do the entire hike back down the park until you reach P2. P2 is a boat dock where a slow moving electric boat shuttles people across the lake. The three docks are labeled P1, P2 and P3. You’ll take the P2-P3 ferry which will drop you off at a large open area with picnic benches, food stands, drinks and restrooms. This is a great place to stop for drinks and lunch before doing the last bit of the hike around the lower lakes.
The Lower Lakes part of the hike is shorter than the Upper Lakes part and doesn’t take much time. The prettier lakes and waterfalls are around the Upper Lakes, but the bigger more impressive waterfalls that tower over you can be seen around the Lower Lakes.
Make sure to go all the way to the end of the hiking trail to ensure you see the biggest waterfall in the park before heading up the stairs back to the parking lot.
If you do the hike this way you’ll make life easier on yourself by ensuring you’re going downhill for 95% of the hike, you’ll see everything the park has to offer in a relatively short amount of time, you’ll save the most stunning waterfall for last and then you’ll end the hardest part of the hike back at your car instead of having to walk long distances or take the shuttle back to where you parked.