This location has seen vandalism in the past 5 years or so , not saying it isn't safe, but truly one does park at their own risk no matter where.
The first thing I suggest to do is try contacting the AT Conservancy in Harper's Ferry and ask about trailside parking regarding any possible incidents at that location.
If anyone knows this information, they do ; call - 304.535.6331 or Email :
[email protected]
Helpful hints on parking include never leaving anything of value in your vehicle. I advocate locking the doors
Also : Look for houses and/or businesses nearby that have a window(s) facing the trailhead parking area and also possible street lights .
Another option : If THERE IS a business within short walking distance that has a well lite parking lot politely ask them if they would allow you to park on their property for the night.
Tell them that you would not hold them liable for any vandalism, etc. that may occur to your vehicle. I'd sign a waiver releasing them from that responsibility.