Idk, I kinda feel the opposite on this one. The old timer trick is fine but you can't catch everything with a screwdriver and a flashlight, because soft spots hide under the rails and near the doors where you won't poke. What worked for me was crawling under with a light and checking the crossmembers for rust flakes, and if the wood looks patched or painted over in one spot that's a red flag. Maybe it's just me but I'd rather pay a shop 50 bucks to look it over than trust a guy I just met at a gas station.