If you want go down to the water, it is possible at this location (Kieler Ufer, N 54 33.181 E 13 40.487).
The most famous place in the park is the chalk cliff “The Royal Chair” (Königsstuhl) with a height of 118 m. But it has the same problem as the Eiffel Tower. When you are on the cliff, the cliff itself is not visible. Therefore, if you want to see it from the side, then go to the second viewpoint Viktoriasicht (N 54 34.250 E 13 39.930), moreover, it is free. Actually, the whole park is free, only the Königsstuhl is paid.
Viewpoint got it's name after the visit of Queen Victoria in 1865.
On the way to the viewpoints, in a 700-year-old beech forest, you can find many beautiful places: lakes, remnants of ramparts and megaliths.
We even found a sacrificial stone. Not real, of course. Though, somebody even put a red paint on it.
Getting there: parking lot is here N 54 33.740 E 13 37.456, further either by bus or on foot 3 km. We walked. Buses run there regularly, so use bahn.de to find a timetable, your stop is Sassnitz, Nationalpark-Zentrum Königsstuhl.