So I had started a new survival world, and I was traveling through Lindon, and picked up a Lindon Sword along the way. Great, I thought, I'll know later when there are Orcs or Uruk-Hai near, since I was planning to travel through Rohan. On my way to the Blue Mountains to pick up some Dwarven gear and possibly some Dwarven Tonic, I switched to my sword in the Blue Mountains Foothills biome, and it glowed blue on and off. I didn't actually see any orcs, but I was scared to death and fast-traveled back to the Shire. I'm a bit worried to go back, but I don't think it will be as bad as fighting my way through Eriador at night. Advice?
In any case, if you have an elven sword and half-decent armor, you shouldn't really need to worry about the occaaional gundabad snaga you might encounter in the Blue Mointains. If an invasion spawns on the other hand... run like hell.
They only spawn in the foothills, not the actual mountains. In any case, their presence there makes absolutely no sense, especially in the western foothills, as they have absolutely no way of getting there! On one side there’s Lindon, on the other side, there’s the Blue Mountains! How would they get there without being massacred?!
Speaking of invasions... Later I was walking throught the Lone-Lands on the way to Moria, and I hear the horn and see the message, "Gundabad Wargs have launched an invasion nearby." So I look up and right above my head is the invasion spawner, and I start shouting, "crap crap Crap Crap CRAP CRAP CRAP FUDGE CRAP CRAP FUDGE FUDGE FUDGE CRAP CRAP" and then I remembered that I had iChun's Morph mod installed, so I turned into a Bat and flew away...