Well first of all, I love the porch on the photo of the house you have on your profile! I used to have an old frame house in North Texas with a wrap around porch and I never thought of sewing on it! "Cool" idea though! My ex-husband made me and our three kids live without an indoor air conditoner and sewing on the porch would have been great! I just opened some windows in the house, turned on a big osollating fan and the kids and I took two cool baths a day to keep cool.
I don't think sewing on the porch is Redneck at all and if anything, you might drum up some business and surely curious neighbors! Sew where your comfortable! I love you already!