Stephanie will have some thoughts about the source and cause of the zombie infestation in my next IC post, as well as a nonlethal (though still drastic) way to use EMPs to shut them down if her hunch is correct that that is what they, in fact, do.
The bomb shelter I mentioned is in the T-Bone's basement. Baldwin told Bo about it in an earlier PM from Welsh. Bo then told Sean (who's now dead) and Kimberly. Baldwin and Kimberly can fill Wallace in on the way to Brownson. Baldwin specifically said it was stocked with food, water, and medicine.
The four sources of additional guns and ammo that I've counted are:
1) Hammond's stash
2) PMS compound
3) Warren AFB
4) Cabela's in Sidney
The plow on the truck can also be used to ram the PMS compound's gates if hostilities become necessary, as Kimberly suggested. Bo came up with the idea of slipping someone inside (Flip or David would be our most likely choices) and causing an explosion in the meth lab to distract the skinheads and get them away from the entrance and any potential hostages. Since meth labs sometimes blow up without any outside help, they might not even suspect that they're being attacked. Someone with less compunction than Bo (Mr. Foo perhaps) may come up with the idea of using a
second explosion from a bomb planted near the meth lab where the skinheads would gather to battle the blaze in order to take them out. Of course, if the skinheads are already zombified then this plan wouldn't work. Zombies will only be interested in eating people and will most likely avoid fires.
Considering the delays, I'd say the compressor has had plenty of time to bleed. Baldwin started the truck quite some time ago. Wallace is already aboard, so it can leave any time.
Note that Michael also knows how to fly a helicopter, as does Mr. Foo.
Mr. Foo will probably want to revert to his original evacuation plan once there is no reason to defend the motel. Being mobile and flexible is part of his philosophy, after all. "Flowing into the void" is the sort of thing he'd favor. There's a page on Urban Dead's wiki on just this sort of thing, called River Tactics, with a few relevant Sun Tzu quotes:
http://wiki.urbandead.com/index.php/River_Tactics
By staying in one place, we'd just deal with wave after wave of zombies, slow and fast alike. Since 90% of zombies are slow, we can avoid the vast majority of them simply by staying ahead of them - though the fast ones are worse, of course. My Urban Dead version of Stephanie Bridges barely survived a massive zombie siege of Treweeke Mall, which was just overrun by hundreds of zombies who proceeded to devour the hundreds of survivors within. I logged on after getting home from work to find zombies attacking her, and she escaped with little time to spare. Many others were not so lucky, and staying in one place didn't work there.