I'm very into the 'flavoured' cous cous at the moment - you can make that up and take it with you. Maybe some cooked meats and/or fish too - chicken breasts, ham, prawns. Hard boiled eggs are always good for a picnic too, and maybe some mixed salads - rice salad, pasta salad, etc. If you have a cool bag, or some way of keeping things cold, then you can plenty of choice - enjoy!
A bit too late in the day, but we had picnic last week and I made a salad from new pots, bacon, hard boiled eggs, tomatoes, mayo and nat yog, lemon, pepper, was delicious, other than that salmon pate with HEB of mini chilli ryvitas