I think you are going to be a really good researcher.
You are doing everything right, and admire your use of the directories, maps, time-frame and use of the library you attend.
Exploring "google's street-view" as you have is truly loads of fun. It's a wonderful way to drive around a city without ever leaving your home.
I've used it many times in American research - and it's amazing to see how many structures are still standing. It was recently made available in Canada and some people weren't too happy with it... (security issues...)
You've been able to get information not available on "Ancestry" such as the directories... which is a real bonus. Also the fact that you plan to do page by page searches is encouraging.
Just forget the gas prices and make that visit. :)
Also, there are many census districts that are "unreadable"... The street names are unreadable, but the people from those records are certainly indexed on Ancestry.
I love "zeroing in" on streets or districts using sites created by Stephen P. Morse-PhD, Joel D. Weintraub-PhD, and David R. Kehs-PhD. Can be tricky to use at first, but once you get the hang of it, it can be a wonderful tool. That whole team is simply amazing.http://www.stevemorse.org/census/index.html?ed2street=1
As mentioned, I've searched by first name only, nationality, YOB, just for Nellie... Nel, Sue, Susan, and even without a name... using the county only... and nothing.
Best of luck to you, seems like an interesting family!!