I don't know about BOBs, but I know that when travelling by car, a couple hundred bucks in small bills is SOP. It solves a lot of problems and gets you out of dicey situations.

It also rewards honest citizens/Good Samaritans who stop and help you out. Most people won't accept "payment;" but the offer is important, and you can say "have a beer on me" or "donate it to your favourite charity." If they still turn it down, say "no problem, I'll just pay it forward;" good people get that.

BTW, in out-of-the-way gas stations, I still see the old card machines. They use them when the lines are too slow, provided you have other ID.