Aholibamah said:
I had thought that the first couple of days of the arrival from the POV of the new folk would be something out of either a horror or sci fi movie, and that my sources of inspiration would be:
I think that would be pretty much spot on unless the town itself was unusual, such as having a large army base attached to it or something. A lot depends on what you mean by 'crawling' with undead, and how well (if at all) firearms and explosives work in the fantasy world.
Figure that about half the town will either go into denial or just be overrun by the monsters in the first couple of waves. No phone, probably no electricity for the most part save for the couple of people with a generator (again, this depends on where the town comes from - a remote rural town will have more resources applicable to their new situation, a suburb town/bedroom community will have far less) means that a lot of people will be cut off and not find out about the danger they face until far too late. Then the cops and other authority figures will probably set up a central location and operate as if the town had been struck by a natural disaster.
In the long term it'll shake out about like this: (1) a small core of people who Can Deal With Things, probably composed of former or current law officials, emergency workers, veterans, maybe a couple of university types, and a random sample of people that have risen to the occassion and find themselves with more smarts, guts and willpower than they knew they had, (2) a much larger population that just goes insane in various ways, (3) a group that crystallizes around a religious figure, (4) group or groups of opportunists who see this upset as a way to finally rise to the top.
Depending on the type of undead, some of the people in the town probably are converted, and show up later. (Hey, open up! It's not one of them, it's old Charley! I live next door to him.)
Some of the townspeople might spontaneously manifest the Sorcerer class. This could be lots of fun

Even more fun would be people who find their prayers answered. But by what?
You will have at least a couple people that want to reason with the monsters and serve to show how the monster works when they get eaten.
For the PC's encountering the setup: They're going to be astounded at the sheer incompetance of most people they encounter, probably comparing them with the worst inbred city dwellers they've known. 1 on 10 might have some useful skills (again, this varies sharply with the character and nature of the town) but even many of those who are used to camping and outdoor sports will have been so used to modern conveniences and materials that things will be a huge shock to them and they'll have a period of adjustment.