Pennsylvania Missing has more information about her, including the belief she was dragged to where she was found, due to disturbances in the grass.
http://pennsylvaniamissing.com/250ufpabushkill.html
It's also mentioned she may have been someone who frequently rode with truckers, based on the sunburn pattern on her neck and right arm.
The way she was found seems so inconsistent with her death by a heart attack. Maybe she was traveling with a trucker and he panicked when she died, not wanting his wife to find out he was with someone else, or he was scared he'd be blamed for her death, but why drag her so far from the road that it took several days for her to be found?
I doubt he contributed to her death, but he might have seen an opportunity when she passed and he kept whatever money she might have had in a purse or wallet. Her clothes look very clean, so it seems likely she would have brought along a few changes of clothing, money for a laundromat and other expenses, etc.