marci - You can buy a mini selection of cheeses & crackers. Large punnet of strawberrries plus cream! Yoghurts. Individual little fruit tarts ( Mr Kipling ) Quiche. sandwiches.
Make some cornish pasties timed to come out of the oven at the time you are about to leave home for the picnic.Wrap them in some foil and then a teatowel and they may still be warm when you are ready to eat them.