I'm playing on Very Hard / hardcoe and im sitting at approx level 14 without having entered the Lucky 38. My goal was to whip the piss out of the NCR pre 38, collect enough NCR tags to hit accepted with Legion, then use the amnesty to spend the rest of the game whipping the piss out of the legion instead (eventually choosing a fully independent ending / nuking them both on lonesome road after I took advantage of the benefits of having NCR like me) . My question is, do I need to have entered the Lucky 38 to get an audience with Caesar so I can get into his tent and speak to Lucius? or can I just waltz in there when I have the rep and get the training. The legion disgusts me, so i've always just slaughtered them, its a rare playthrough that I dont have their assassins after me before level 10 lol

No, the trigger point is actually The Tops, if Benny is killed or flees, Vulpes or his replacement will be there.

Okay - and thanks for replying - then the question sorta still stands then. let me rephrase. do i need to enter the strip to get to caesar's tent ? or can I walk in there without the 38/benny/etc stuff done first? Basically, I would like to save the reputation amnesty for as late as possible but im also anxious to get the move.

in my DT 8 light leather armor im starting to get mowed down before i get close enough to play mortal kombat with my enemies and would like to use legion assault to help me close distances.

Master stealth kills. I completed the Nelson quest in the NCR's favour and only recieved negative Legion rep in the end when I beat the quest. I recommend the silenced sniper rifle and head shots.

And no, you need to trigger the recovery of the Platinum Chip/let Benny flee for the access to The Fort to be permitted.