Go to yahoo groups and search for secular homeschool groups in your state and town. That may call up some you are finding on other searches. Looking at email lists is an easy way to get a sense of the local scene. I will say in my area secular groups were not the first ones the largest or first ones I found, but ultimately there turned out to be many nonreligious homeschoolers in my area. I echo other posters that especially during elementary school there are daily options for co-ops, field trips, and social activities.
I would also remember that homeschooling is not a forever decision. You could try it for fourth grade and see what happens. Best case scenario you find a good community, enjoy the academics together and discover something great for your family. Worst case scenario you don't find a lot going on during the day and the afterschool activities you put together don't fully meet her social needs, but you had a fun academically satisfying year together. Doesn't seem like too much of a risk to give that a try.
