Gwen,
I'm also waiting for NC myself, that's the majority of my research. But for the families which you say you can't find them in 1930 or 1940, so far, yet you're pretty sure they were there, you may want to try by first names, if possible. I've had census years like that when for some reason they were just not listed under their own surname, especially if they happened to have someone else with another surname living in the same household. And then, of course, there are those times when the transcribed name is entirely wrong in the index. Just yesterday I found a death certificate on Ancestry that was indexed as "Watha Pardie", while the actual name reads "Martha Parker" . There are always cases like this, and it is often the answer to "missing" names.

Deloris