I usually pay for the VIP parking, it is about $11 and the extra few dollars is certainly worth it. You get to park much closer to the actual entrance of City walk and my feet are thanking me at the end of a very long day.
I thought they just raised it to $9.
Anyway, if you want to park for free and walk across the street, it can be done. I wouldn't do it with kids, as it would tire them out. http://www.nogodforme.com/offsite.htm