As others have said, skip Sacramento, stick to the coasts (Hwy. 101). If you ditch the truck, you'll also have a much easier time driving and parking in the cities -- parallel parking in downtown anywhere can require some dexterity. Look for a used Civic hatchback or similar.

While you're in San Diego, you can go a certain distance into Mexico for a day trip occasionally without much commitment -- Ensenada, easy. Hotels are easy enough to come by that you can head further south for a weekend or so, to see more of Baja (maybe San Felipe). You'll notice that the further you get from the border, things get less sketchy and more interesting. I only mention it because you started by mentioning you'd like to see "something else", and you can definitely cover more than the U.S. west coast in 6 months.

Another day trip from Long Beach that probably wouldn't occur to you: Take a boat to Catalina Island with some friends, rent bicycles, get blitzed, eat sushi. It's a resort town done right -- golf carts instead of cars, lots of beach, and easy food, drink and sightseeing. One day is enough.