Fred,
Congratulations on your new LM Ashland. It is a beautiful rig.
I have lived in Southern California for 55+ years. Any of the SoCal beach RV parks are going to be tight and expensive. Many folks though, are willing to pay and stay for the beach ambiance. That said, if Newport Dunes is close to family and friends just go for it. It is not like you are locking yourself into a lease for the next six months. I know some of my neighbors really enjoy it, although it is not really one of my favorites.
Our go-to park when not at our California home and visiting in SoCal is Prado Regional Park in Chino (Back Loop).
It seems somewhat rural, but is close to Long Beach and all of LA-south and Orange County.
Also, a little further south, San Clemente State Beach Park and San Onofre State Park (San Mateo Campground), are also nice parks, right off Interstate 5.
IMHO, Huntington State Beach (Bolsa Chica) would be a FAR WORSE choice than Newport Dunes. It is nothing more than a parking lot for $75 per night. Stay away, it's a zoo.
Whatever you decide, have fun, enjoy your stay and your new rig! PM me if you have any questions. We are in Orange County until May. Trace