The guys I'm counting are Rick, Shane, Glenn, Daryl, T-Dog, and Hershel. The woman is Andrea. I don't see the kid or any of the other women as able to fight.
Andrea has already proven she can hit at distance (not mortally) so maybe she could be over watch.
My thoughts are that the raiders are sending out intel patrols of from 4 to 5 (like the ones at the bar). Probably at least two intel groups a day looking to locate new supplies and the next night's campground. (The kid said they moved everyday.) That would leave about 20 to guard the women and supplies in the raiders camp.
Eventually, the raiders would come across the farm. The one guy who escaped in the truck has provided intel to the raiders that there are at least a few armed guys in the area. I'm sure the raiders see them as a threat as well.
I've got a few ideas about this but want to see what everyone else thinks.