I FO3, you could literally have 75-80 Sneak, and Raiders or Super Mutants would obliviously walk right up to you, less than a foot away, shouting "Who's there!?!?!" without noticing you. Stealth Boys worked identically, in that they made this 100% effective, regardless of your level of Sneak. Obsidian completely reworked the way Sneaking functions, in New Vegas, to make this abuse impossible. So like Stanislao says, Cazadores' high Perception means they will NOTICE you, even with Stealth Boys. Any method you use to try and skirt around killing them will only make the trek potentially less hazardous, but it will NEVER rival the level of "safety" you get from actually killing them.
Additionally, because of the engine's shittiness (yes, we just can't escape it) it's very, VERY dangerous to save while out in the field, or at least certain contiguous sections of outdoors, because loading can (and often will) cause new batches of creatures to spawn. You wouldn't want to make it past a couple trees, having successfully avoided a group of Cazadores, saved, then accidentally aggro'ed some others, only to reload and find yourself staring down a new group of 5 that will always be there when you reload again. That happens, and once you get caught in the loop, the only escape is an earlier save (or lightning-fast murder/escape).
And, again, regarding your status as Very Evil.... you SHOULD probably be considered a very bad person if you steal prolifically. That's bad, no matter how you slice it. Killing in the post-apocalypse is truly a grey area; maybe they're out to get you, maybe you had no choice. But theft is always a premeditated act; you don't "accidentally" lift that rifle off of the store shelf. You're actively planning on doing harm to others, it's just isn't physical harm to their physiological well-being, it's more psychological and economical terror. If you think you can perpetuate doing this regularly, and argue that you're not doing anything bad... that's very egocentric evil, so the Very Evil title is well deserved.