Tiles, we'll make improvements to how all this works in future. For now, if you go to all the layout tabs (e.g. Terrain, Shaders, etc.) and close the 3D Preview for each of those, they should remain closed until you open a new file. That's not as good as you wanted it, but at least it works within a particular file session. You can then open a single 3D Preview in a separate window (see the View menu), and you can pause that and have it do what you want.
Matt