Chandeliers and Outdoor Weddings - could TOTALLY hang a chandelier from the big tree. Could then install the chandelier in your house. Craigslist has them for cheap all of the time. Could even use just a candle chandelier and it would still look gorgeous.
Pretty backdrop for the wedding party table. Tulle and twinkle lights make beautiful wedding decor. Maybe do a solid white tulle with lights for the whole barn and this accent in red behind the head tables?