Just a quick two stage multi for your caching pleasure. Park at the suggested parking - any other location is not allowed. From the parking coords, saunter over to the reference point to find a sign that lists five things that you can't do at the lake. What's the third thing that you're not allowed to do (enter the word as shown on the sign)?
You can validate your puzzle solution with certitude.
N qrgnvyrq uvag vf tvira va gur purpxre.