How does one so the glitch in the ship shack where you can buy something you can't afford?

was having an amazing run that was well on pace to be sub 30 (Glitchless) and right as i jumped off the dam to get to the rock some legion fuck shot and crippled my leg making the already practically impossible jump completely impossible

so im trying to do glitch-less any% and i keep having an issue with NPCs, more specifically the super mutant at black mountain that warns you about proceeding, The NCR soldier in camp Mccarin when you get off the train, and the Caesar's messager. How do i avoid the forced dialogue with these NPC's? also when i get to the point where you interact with the omertas yes man doesn't appear in front of the tops, why?