That's a traditional set of plants, for sure. And they can grow together really well. I think it works best for corn and beans that will be used in the mature state -- dry corn and dry beans. I've always been too big-footed to tiptoe through big winter squash vines to get at sweet corn or to pick the green beans. Better to just plant and let it all  grow undisturbed until the fall. I've also found that it works best to plant the corn first and let it get a few inches high before planting the beans. Otherwise, some fast-growing pole beans planted at the same time as the corn, can just overgrow the corn.  Scarlet runner beans are one of my favorites of all beans. Their big dry beans are so substantial! Enjoy your Three Sisters this season!