Eventually I went to Cottonwood Cove to try to get to Caesar to talk. Well, I get swarmed by the Legion.
So I try again with a Legion outfit on. I make my way into the camp, but get found out by the dogs and killed again.
So I try getting some NCR dogtags for the Cottonwood Cove guy and get my Rep back up to Neutral with the Legion, however THEY STILL ATTACK ME ON SIGHT OR ON SNIFF WHEN I WEAR LEGION ARMOR.
I have tried many approaches to this, including having nothing on, getting rid of my companions, etc. Nothing seems to work. So, Bethesda, PLEASE MAKE THE MARK OF CAESAR DO WHAT IT IS SUPPOSED TO.
I'm kind of stuck in the main quest here as I can't get to Caesar without massive firepower.