This is the bonus cache for the Adventure Lab, A Grand (Lake) Adventure. You must, of course, complete that AL to get the coordinates for this cache. You can find that AL at https://adventurelab.page.link/osRS .
You will want to drive to this one. Some folks may consider this within hiking distance, but the road to it is not pedestrian friendly. However, it is possible to park practically right next to the cache.
It's a small camouflaged box with a log, pencil, and some swag. I'm rating this terrain as 2.0 and some might think that's too high. If you're getting into serious terrain issues, you're off base. Practice your usual stealth and stay safe!
Note: This cache is NOT at the base of the poles! See the spoiler pictures!