Not any difference between Primitive and reg sites as far as I could tell. No electric at sites, nor water hook ups - water is available at side of roads.. Lake access just depends which site you snag. If you get the right ones then yes real simple access. NOTE I was there in June and lake was very low.

We didn’t explore the whole campground, but from the primitive sites, we biked a very short way down the road (maybe less than 5 minutes biking?) to a beach/boat ramp area and went swimming there. There were a bunch of families there and the beach was super easy for swimming access. I believe the primitive sites were closer to the beach than the full-hookup sites. Hope this helps!

Primitive has NO water access. It is on a marsh.