@oceanembers said:

I wonder if there's a plugin to give all containers the default material?

There is a plugin that takes the material out of instances (components/groups) paints the faces directly with it in one go. That would solve it...

It also has a lot of other practical but dangerous tools:

Thomthom's Material Tools

These are all great suggestions, none of which I've tried. I'm a self-taught Sketchup user, so I don't know many of the tricks. I will give these a shot! In addition to this, is there any hardware upgrades I can do to help speed things up? Is a 285 MB drawing pushing the boundaries of what Sketchup is capable of? Thanks for your insight!