Looking at the map, Jarman Gap is the southern park boundary, separate from skyline drive terminus. At least the north terminus and park boundary is at a place called Possums Rest and not adjacent to or near skyline drive entry station near Front Royal. Just go after Standard Kirk Locale and you’re good.
I am pretty new to the ultra scene but have done my fair share of backpacking in the park. I would love to find some people to run with in the park and maybe attempt this one day! I think sub 24 hours could be doable and even more so with a group to push with! Maybe establish some vertical FKT’s on places like Mary’s rock and Old Rag too!
If this forum isn’t dead and there’s a few people interested in doing this in June or July contact me please!