Not Worth a Hill of Corn and Beans: Fitz is one of the three meat suppliers for Camp McCarran on Farber's list. He can be convinced to trade with McCarran either by being told he'll be paid in caps, or by being persuaded to trade in exchange for vegetables via a Speech 60 check or a Barter 60 check. Either skill check results in a larger reward than the former option.
There is a spawn point for Legionary assassins at the overpass close by who can reach the rest stop very quickly if the player character has just fast travelled to the location. It is very easy for Fitz and/or Lupe to be killed in a fight with the assassins.
Lupe has a greater chance of survival than Fitz since her weapon (a 9mm pistol) allows her to attack from range, whereas Fitz will charge at the assassins with only a knife and will most likely die even if the player intervenes and attempts to prevent his death.
A workaround can be to approach the Grub n' Gulp rest stop from a different nearby location so that the assassins are drawn in a direction away from the rest stop, outside of Fitz and Lupe's detection.
PCPlaystation 3Xbox 360 While recruiting meat suppliers for Camp McCarran during Not Worth a Hill of Corn and Beans, it is not possible to recruit Fitz's services if the player has already asked Farber if he needs help. Fitz may ONLY be recruited if Farber has indicated there is a supply problem but the player has NOT selected the dialogue option, "Can anything be done to improve your supplies?" The same is true of Ruby Nash. [verified]
On PC, a workaround is to type set VFreeformMcCarran.iMessHallStatus to 2 in the console before talking to Ruby Nash and/or Fitz.
PCPlaystation 3Xbox 360 Both Fitz and Lupe lack an AI package to keep them at their storefronts. If anything pulls them away from their stores, such as nearby combat, they will remain where they stand and will not return to their storefronts. [verified]