Picture #2 looks like sawfly larvae gathered on a Smilax sp. leaf.
What does the whole tree look like?
How big or small is the tree?
What are the soils and moisture regime like in this state park site?
What are some of the associate species present with this common tree?
What I think it is would be a small tree or large multistemmed shrub. Observers would have noticed that not every plant has fruit present. It would likely be in the draws or ravines of the landscape, where moisture levels would be higher than on drier steeper slopes. It could occur on limestone based soils, but would likely prefer pH in the 6.0 range. It likely has tolerated a noticeable level of White-tail Deer foraging. If one had crushed a leaf and smelled it, one would have noticed a significant odor/fragrance shared by the unripe fruit if similarly crushed.
If you have any of that information to share, it would support identification assistance.