There is a bunch of configs already here, and even more threads detailing out how to make your own.
And objects dont just stop loading when you drop graphics. They may become distorted but they dont stop showing up. r_gfxopt_dynamic_foliage "0" will stop static objects from showing up until you get closer to them. Its incredibly annoying and should be left at 1 at all times.
Picmip determines the size of the mipmaps to be loaded. The higher the picmip, the smaller size mipmap will be loaded, and everything will look a lot muddier.
Low resolution and in game menu graphics turned down should be mandatory if your computer is low end.