I also carry American Express for a card, they are by far the best for fraud protection. I only have one Visa and one American Express Card and it has done everything I need to do, now on the flip side to continue your path with cash only, the things that you could do is use your banks debit/visa card or if you don't won't to explore that route, then I've seen many of the pay as you go credit cards in 7-11 that you add dollars to the card just as you would a pay as you go card. You would use it when you would absolutely need a credit card but I'm not sure if the rental agents for cars would accept that.

https://www.allaccesscard.com/prepaid-de...CFQITswodcT6gFg

https://www.netspend.com/

And of course a forum that talks about them being a rip off but for emergency may be a option

http://forums.moneysavingexpert.com/showthread.html?t=311257