not sure if its been asked but..

Well things didn't pan out all that well when they decided to stay put so... Like Barbara said, they could've left Cooper and his wife and daughter behind (of course we the audience know the daughter was a goner anyway) and gone for help. They might've run into that group of rednecks sooner. Then again, it might not have been good for Ben, but it would've been worth a try imo.

Don't eva let nobody tell you you ain't strong enough

No kidding. Yes, the zombies moved slow, but imagine if you ran constantly, you'd get so tired out and move as slowly as the zombies, perhaps even slower. Not to mention if you did run, they'd follow you one after another and you'd be leading an entire leagion of the undead wherever you went.

As for staying in the house, well, there are ups and downs to that kind of situation. There's the claustrophobia thing to take into consideration combined with the fear of not knowing what's going on. On the other hand, you've got walls separating you from the zombies as well as places to ambush them until you thin out the numbers enough that you can make a run for it. There were plenty of blunt objects in the house so it's not like the gun was the only weapon.

Why is it no one ever seems to get it through their heads that blades and clubs don't need reloading?

I watched the movie once again today.

It's odd looking at it now - the things done wrong. The actions recommend in Max Brook's "The Zombie Survival Guide". Boarding up the windows was a good idea. Moving all the food upstairs and filling the bath tub with water would've been a better idea. As Walternate mentions, the stairs... don't block it - chop it up. I'm sure the basement had an axe or two. The ghouls couldn't reach them. They could've waited it out on the second floor. Have a sign out the window 'We're Still Alive!' or something like that.

The other thing that caught my attention was Johnny; Barbara doomed him. She kept stabbing that zombie with the funeral cross, the spikes that held it onto ground pierced the undead fellow several times. She then accidentally stabs Johnny in the hand - infecting him.

Going back to the topic. Barbara was not going to Evans City. She was trying to get out and find help. Barbara wasn't following the road. In fact it was dumb luck she was found by those rednecks. She was kind of walking aimlessly in the woods.