TEC -
I get what your saying about the camp ( a.k.a. holy city ) is like a DMZ line that Satan and his forces are not allowed to cross. A city of refuge as it were; however I haven't seen anything that says there won't be another test of loyalty. Just the fact that Satan is loosed again is a test for all intelligent creation in and of itself. Those who choose to remain loyal to God can have safety in the holy city/camp but that doesn't mean that they are not tested.
As you quoted, the bible says that there is a first resurrection, which implies that would be more following that. Back to my point...If one lives their course on earth faithful until their death and then is resurrected in a subsequent resurrection; than that individual would in fact be in line for a second testing to my original point.
Only that those who are of the first ressurection cannot be destroyed and are immortal, and it is my understanding that they are in heaven where Satan is banished from so Satan has no direct access to them. I don't think that means that they cannot still be influenced though.
Whatever the case; the fact that this is God's plan after the 1000 years after all the misery that he allowed mankind to go through over the ages is questionable at best. He doesn't want anyone to exist that doesn't agree with him. I don't believe someone who holds you accountable for what your ancestor did and demands worship while holding your life hostage deserves it.