1. When you're drawing paths with jagged lines, it's much more efficient to use the pen tool rather than the pencil. With the pen it pretty much takes one click per point rather than two as you were doing it.
I didn't know that, I've never used the pen tool before.
2. Instead of messing around trying to guess how big your map is, you could have just selected all your shapes and used the "Resize page to Drawing or selection" tool that is right under the size boxes. It's just something I recently found that's really useful :)
I actually didn't know about that either!
3. I'm not really sure what CRL+SHIFT+6 does (I couldn't find it in the menu anywhere) so maybe I'm totally wrong on this, but wouldn't it be much quicker to just use CTRL+-? That's what I use, but I'm not completely sure on this one.
It's really CTRL+^ , but I say "CTRL+SHIFT+6" because that's really what it is. (Well, now that I think of it, it may be different in other countries, I don't know.) I believe it's called the Exclusion tool.