Whenever I try to edit the city I'm making (The Hive) lots of things are invisible until I double click on them. This makes landscape editing nearly impossible, and in general prevents my from getting a feel for what my city looks like. Is there a fix for this, or is my computer too crappy or something?

I believe this is an LOD issue

Wow, even houses don't show up a lot of the time. I understood when Mountains weren't appearing, but jeez, anything bigger than a person basically will sometimes go invis on me.

You can refresh the cell and force items to load by pressing F5. Creation Kit minimizes resource usage by not showing large meshes. Mountains and other large statics tend to become invisible when you move from the cell they are placed in or from the immediate vicinity of that cell.

Thanks for the protip, that is going to make things MUCH easier.