Amarillo + Simcoe is possibly the perfect base for any hop-forward American style. I usually use 3-4 hops in my APA's, and unless I'm going for something specific, it's generally from these hops:
Ultra (noble-style hops add a nice complexity in combo with "C" hops, IMO)
Cascade would work perfectly fine here as well. For my APA's I do 1/3 of my IBU's as FWH, 1/3 at 60 min, and 1/3 from 20 minutes or less additions (usually hopbursted). Sometimes I will skip the 60 minute addition and split the IBU's between FWH and late hops. I use about 1/2 ounce of each at flameout and 1/2-1 ounce of each as dry hops.