That's a bit optimistic.....
Welcome!
If you just want to get there without sightseeing, it's about 5.5 hours via I-15 all the way if you drive close to the speed limit. There shouldn't be any traffic issues except on Sunday - I-15 gets very congested with everyone coming back to LA from Vegas after a weekend. Of course, rush hour during the week will be congested around LA and SD. If you wanted to make it an all-day evolution, I can recommend a very scenic route.
I can recommend the Holland Burger Cafe in Victorville. It's been featured on the Diners, Drive-ins, and Dives show on the Food Network. Get off I-15 at the CA-18, D Street, Historic 66 exit and head northwest out of town toward the airport, it's a bit over a mile from the freeway.
Another possibility that's closer to San Diego is Tom's Farms just south of Corona. It's right at the Temescal Canyon Road exit.