Suggest weekdays...
Nice location along Merced river...was quite surprised. Most sites have shade. The river is very high at the moment, so swimming is currently prohibited.
Unfortunately it was a mess Fri-Sun mid-June 6/23 with loud Norteño music being blasted from multiple campsites and the day/group area in particular. Very loud and non-stop. Lots of large families having fun, but was seldom a peaceful moment, even late into the evening.
Bring earplugs, or maybe try weekdays? if you prefer R&R without the noise pollution - SP employees don't bother to deal with the problem.
Site12
Month of VisitJune