Ha, I'm more thinking of end-game, lvl 21+. I don't want to mine the entrance because the mines love friendly fire. Especially with caravans. Heavily invested in and equipped caravans.
You don't have to place a permanent mine field near the town, it only has to exist long enough to take down those 4 Super Mutants that come around. Once those are taken care of the town is safe and you don't need to worry about anything anymore. So it sounds tome like you're way over-thinking that whole scenario. I've never bothered teaching them anything, I just kill the Super Mutants that arrive shortly after freeing Red and Shorty. And the town has always lived happily ever after.
And the problem is that an Albino Radscorpion, which spawns anywhere normal Radscorpions spawn, has fully 3x the health of a Sentry Bot.
Again, you're over thinking things. The only spawn points in that area are general Wasteland spawns, not just Radscorpions, meaning that any creature can spawn there. So the odds of having an Albino Scorpion appear in the area are fairly rare. Then it would have to wander off out of his designated zone in order to attack Big Town, which will be an even rarer occurrence. They're only allowed to wander an area of 1024 units, unless they're attacking something.
As of right now, I need to know if teaching them to sneak will save them from a radscorpion, ghoul reaver, or mutant overlord and the like.
They will never be attacked by a Reaver, there are no Ghoul spawns in the area. And an Overlord may be possible in that trailer nearby, but the patrol area there is so small that he would never end up in the settlement, unless he was following you in. So Radscorpions are the only possible danger they could face, but the odds of a really tough one showing up are slim.
PS: And this thread really should be in the Spoilers section.