I got to New Vegas and got the Mark of Ceaser and the quest..

But I still need to wipe out more Legion....Camp Forlorn Hope for example...still need to do the assault on the town bit.

And I know Boone still has a hankering for whack a moling Legion.

The guy said my past crimes against Legion are waived I need to go see Ceaser.

But what happens if I kill more Legion troops before then ? Will the Mark Of Legion still work later on ?

Or does killing Legion after getting the Mark mess things up?

I don't think it would mess anything up, but killing more would probably make you unable to even get to Ceaser because everyone will hate you.

Ughhh...

Camp Forlorn Hope save is hours ago....

You'll probably end up having to kill all the people at Caesar's place if you turn the legion against you again. At least that's what happened to me. I had to get the chip from Benny, who was hanging out there lol..

Why don't you just go see Caesar, get that taken care of, then go back to Legion killing?

This.

Also, you can get up to hated with the Legion and they'll still take you to the Fort without incident. I kept neutral for quite a while, then dropped by saving the family in Cottonwood Cove while Boone sniped everything (so I took the faction hit from freeing the slaves, none from the Legion deaths). I still had to knock off Nelson, but I waited until I had reached a point with Caesar's quests where I didn't care to help him any longer (in my case, where he wanted the Boomers' help- no way was I letting them drop fiery death on my ass).

I'll do this...