I agree, ask the Amish -- and start trading with them now. There's no reason to wait for TSHTF. In fact, if you've already made contact and have some trade going on beforehand, you'll be all the more prepared in case you need to do it for survival purposes, instead of a little extra money.
I'm learning all the time. I can provide a recent example of a missed opportunity. An older out of work guy I know had a fantastic canvas hunting bag and was trying to sell it. I gave him my best offer. He said he'd keep it in mind, but maybe wait until the end of the day. Someone else offered to trade him for a modern backpack (I have several of these) and he took their offer. So by limiting myself to money, and not thinking about trading instead, I missed an opportunity. Never underestimate trade without money.
The Amish have a materially simple lifestyle, so you won't be trading jewelry, art work, etc. But just ask them directly, and think about both men and women since there's gender differences in what they do/need. I've seen some Amish simply shop at regular stores, even for certain grocery goods, hardware, cloth, boots, etc. The stuff on a mercantile store shelf 125 years ago. If you could provide it in higher quality, cheaper or more wholesome in some way, you'll have your trade network.