There are electric pitches available at the entrance of the national park. You can register for one at the information house. If you need to use the toilet, you can obtain a key to empty it. Drinking water is also provided for your convenience.
I slept for one night. The hike around the lake is really nice to do. There are dry toilets available. I didn't sleep at the caravan site because it seemed to be for a fee, but I slept in the parking lot. Just be aware that the park's explanation sign mentions that overnight stays are not allowed. There's a good amount of hikers passing through. It's a friendly place.
A new operator is offering a package for the 2022 season. The price is 32 euros, inclusive of electricity. The campsite provides fresh water and has facilities for emptying chemical toilets. Additionally, there is a sauna available for rental at a discounted price of 25 euros. While it may be a bit pricey, I believe it is worth it due to the beautiful location.