Ok, I finished the mission "Lucky Old Sun" a months ago. My issue is that after I did this mission, I learned that the NCR needed help at Camp Forlorn Hope. Well, my I began on this mission called "Restoring Hope". In the beginning, the player is to find NCR guys at HELIOS One and well the Legion has taken over HELIOS One after "Lucky Old Sun". Now I'm stuck with a mission marker on my Pip-boy 3000 that's pointing at nothing but air. Any ideas on where to find these NCR guys?

Go East from Helios One and it's not that far.. cross the hwy and keep looking around the small hills before the large hills on the way from Helios One to Camp Forlorn Hope.

Look here and scroll down, it will have a map location for the supplies.
http://fallout.wikia.com/wiki/Restoring_Hope

And in the future if your going to slaughter the NCR you should probably do so, after your done working with them.