I don't know if the silver will do much more for you than cash - a couple grand in cash can certainly be a good idea in a get home bag. The gold. is a good idea too.
Just make sure you have lots of small bills too. Lots of $5's, $10's, and $20's. If your cash is all $20's, $50's and $100's you might end up significantly overpaying for a $10 pack of batteries or roll of duct tape.