Mastercard was accepted in more places than Visa... and withdrawal ATM's are around, though not prolific, need to ask where.
and AMA offers free exchange: ask for some smaller bills for immediate use (in drink machines, vitamin drinks when you first arrive to get over jet-lag etc),
How much? enough for everything enroute that can not go on the MasterCard. Mostly for 3 or more meals a day.
having ended up barefoot to a few unexpected dinners, I recommend taking the smallest briefest socks that will fit rolled in your pocket: below ankle sport socks (MEC) of solid colour that you could put on in times of social discomfort as often I found it too wet too hot to bother with socks avoiding blisters from waterlogged soles. For comment on them go with a pattern, innovation always seems to be appreciated.
Timberland has some soft aerated shoes with linings for hiking that the backs flip down on to become slip-ons.
And like small socks, take a small fitting yet larger than small rectangle, cotton or linen facecloth that acts as a multi-tool from hand/face-towel to wrapped around your head, dry or moist. Inadvertently mine would always end up drying out by hanging through my belt loop. edzard