Using CG Textures is completely valid. Plenty of industry professionals use that site as well, it's hardly cheating. As long as you don't rely on a site like that for EVERYTHING, otherwise people start to recognize stuff and it comes off as laziness.
I use that site myself quite a bit, usually for grunge overlays and such. Even used a metal texture from there as an overlay for the zombie sawblade. Especially nice if I don't want to be bothered going outside to the cold cruel world with my digital camera.
How about some corrugated metal shanties and worksheds? Maybe some sawhorses, etc, things like that.
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"Your mom goes to college."