They say that to many 100 years is a short time. For those of us on the west coast 100 miles is a short distance. Be prepaird for long drives to get to places.
Plenty to do in the southern part of the state. Sylmar has the Nethercut collection which is mostly cars. There is a second part which one needs to make arrangements for which is a Museum of industrial arts. There they have one of the largest pipe organs, The rest of is is pretty amazing.
Nethercuts founded Merl Norman cosmetics, most of the cars were purchased new. They also have private rail cars.
The Desert is also worth a visit. Getting a bit late in the season. There are places where one can rent ATVs and such. Some parks are for offload use.
There are the usual amusement parks, so called studio tours and the other usual stuff that can be found almost anywhere. For the more offbeat there is Griffin park and the Descanso gardens in Flintridge.
Concerts and stuff are also found in the usual places. Vegas is a day trip away.
The central cost up to Santa Barbara is also nice. They have a wine growing district there. Much closer than Big Sur which is 100s of miles from S.California. These parks are popular at this time of year. Reservations are a must. The Hearst castle is well worth a visit.
South to San Diego also has a lot of attractions.
I myself am located 500 miles to the north near the wine country and of course San Francisco. Which is a world apart.