Best post processing for filling in background in CS5

[amumonamission]

Sometimes when I am doing a mobile shoot due to space restrictions I have to use my smaller background, that sometimes means that the shots I get have the family/people off of the background at the edges. I usually fill this in using the selection tool, refine edge and then I fill the background that way. I feel that there must be a better tool for the job though and wondered if anyone had any suggestions?