http://www.familyfreshmeals.com/2015/01/over-50-healthy-work-lunchbox-ideas.htmlfound this online and it has some good ideas!
I know it's not healthy but once in awhile we like fried chicken, potato salad and baked beans. All those things keep well in a cooler.
Peanut butter and jelly sandwiches and fruit are a favorite.
Pasta salad is also good. Make ahead.
I remember when we had picnics when I was a child (way back when) we had thick sliced bologna and cheese sandwiches. Everything tasted better camping!!