spread it around
I use more plastic then cash. Plastic works nearly anyplace except small mom & pop roadside eateries. I keep a designated credit card in the handy right sleeve pocket of my Road Crafter suit; some cash maybe about $30 in a plastic waterproof zip-lock bag in my coat pocket; and my wallet with ID, another credit card, some cash and my passport in ziplock bag in the inside breast pocket of my coat. Most other cash is packed in my luggage so inaccessible and safe through the day, unless I unpack.
The handy credit card in my sleeve and some casah in a handy bag in my pocket is that I can go all day without touching my wallet or important ID; so I won't misplace important documents accidentally when I'm fueling up (either my tank or my gut).
I also carry emergency contact information in an external pocket, that hopefully will be easily found if necessary.