They actually filmed part of this down in Metairie, Louisiana just off of New Orleans. They rented out an abandoned car dealership left over from Hurricane Katrina to park all their trailers in.
I found this out when I went to a Subway on Veterans Blvd in Metairie for lunch one day and noticed they had a framed, official looking letter with Sylvester Stallone's picture at the bottom and his signature. I asked the guy behind the counter what the story was with it and he told me Stallone himself came over to get a sandwich. Afterwards, he gave the owner a letter requesting if their business could leave the lights on after closing down while they filmed across the street, that would be great.