If you are stuck on the we will all go together, here is a small guide.

First, talk to Astor and accept his quest.

Go into searchlight with rad x and rad resist clothing and pop some rad away every once in awhile. Kill all ghouls. The ones with knives are te ones with dog tags. Collect them. They are at the center of the city and down the road across the bridge starting from the ncr tent.

Once you kill them, find a white door house north of searchlight towards the air field and enter. Either kill the friendly ghoul for his dog tag or do his rather small favor of killing three huge rad scorpions outside of his fore and ask for it after you clear them.

By now, you probably have 9 out of ten tags. Travel to Novac and wait 3 in game days. Then fast travel to searchlight again.

From the ncr camp, walk pay the bridge and down the road. A dead ncr ghoul with a tag will respawns here and you can take the tag and complete the quest.