dipbait, there could be several reasons you aren't finding fruit. If it has been as cold there at night as it has been here, the fruit has already fallen. If that is what has happened, it is likely that you won't find anything on the ground either. Once they fall, what is not quickly consumed by animals like coons, skunks and squirrels, rots extremely fast. Here around Topeka, I picked most of my Paw Paws 2 - 3 weeks ago.
Another reason they don't produce could be this. If you find a large grove that does not produce or produces very little, what you could be seeing are trees known in the Paw Paw community as "clones". These trees grow from the roots of one "mother tree" (a large older tree). These trees are genetically the same. The vast majority of Paw Paws cannot self-pollinate; they must have pollen that is genetically different from one another. There is speculation that one variety can do this, but it has not been proven. (Ironically enough, it is the Sunflower variety indigenous to Kansas). So, you need two genetically different trees to pollinate, and the larger the grove of trees of the same genetic code, the less your chances that pollen from a genetically different tree is going to be able to travel that far to get there. Consider, too, that the Paw Paw flower has a slightly bad, rather putrid smell and is not brightly colored (visible or UV) and so is not frequented by honey bees. Flies, beetles, etc. are relied upon for the task.
A third reason is that sometimes a patch is hit with a light frost in the spring. The flowers are pretty delicate, and it has been my experience that even the slightest frost ruins the flowers, pollination, and the subsequent crop.