It's easy to extend and/or switch the location of your rental after pickup. More information on that can be found in this blog post. As for pricing, it's really impossible to know. It could easily be more, less, or the same. Typically though, if you're returning in the same general area (SoCal in this case), the charges won't be too bad whereas returning in a different state or region of the country could result in a significant re-price situation.