1. On a Monday morning during rush hour, any of the places you're looking at is going to be a nasty commute to downtown LA. Santa Monica would be the shortest because it is closer to downtown than the others. Torrance would be the next easiest commute. Cable, Chino and Santa Paula are probably going to be a least an hour during rush hour, but you should talk to someone who goes to downtown on a regular basis to get an accurate length of time from each location.
2. As a general rule, smog is less near the beach and the temperature is cooler than it is inland. Most people like that, so prices are higher. However, beach area airports often have a marine layer that hangs at about 800 to 1,200 feet above the ground, so it limits VFR flight until it burns off later in the day. Inland areas are more affected by smog. Visibility on the ground is often at about 3 miles. The good news is you can be on top of the smog at about 1,000 to 3,000 feet agl. I've noticed that many times Cable is VFR when other area airports are still under the marine layer. As you move toward the desert, you can have clear VFR almost every day.
2. As a general rule, the closer you get to the beach, the higher the prices, and the more you move inland, the more you get for your money. However, there are plenty of exceptions to this rule, so it helps to work with a real esate agent who knows the local area. An agent who knows Chino and Upland (Cable) is not likely to know much about Torrance or Santa Monica. Southern California is huge, with millions of people living here.
3. It's hard to know what real estate prices are these days. So. Cal has been hit hard by the subprime mess, so real estate values have dropped significantly over the past year. I think you should be able to find a good deal.
4. This should be possible at any of the areas you mention, but my guess is that you'll end up near Cable, Corona, Fullerton or Chino.
5. Plan on living in suburbia if you want to be close to an airport. There's nothing like Meigs in So. Cal.
Let us know where you end up, and welcome to So. Cal!