Besides that, you need people to defend the cader which with exception of the "popular" spots, you will never get. I've tried trust me, to cade in different spots for each map but it's always the same: zombies go for the solo caders/fewer ppl in the cade first and bam, "popular" spots get crowded and survive last.
Considering your suggestion(NewPueblo's), I could think of something like giving buffs to solo caders or cades with less ppl on them, but then again, I'm not sure how you could code this.