I love the look of madras if it is done right. The cotton fabric serves as perfect inspiration for an outdoor summer gathering. You could even use the plaid as your July Fourth backdrop if you find the right color combination. Layer it over a burlap tablecloth and you'll have the perfect outdoor setting.
The perfect picnic setup deserves the perfect outfit as well! I love this madras shirt from J. Crew and these metallic white cuff shorts by Alice + Olivia will dress up the outfit just a bit. These suede taupe sandals from Victoria Secret complete the outfit. I actually have them in black and wear them often!