$75/day on the road in Latin America (or most countries) is doable. I have done x3 trips to Panama and back, I average about $100/day on those trips.
Fuel is always been the biggest expense for me with food/beverages next. It varies though, Baja is easy on $20/day if you camp for days-weeks in the same place. Costa Rica, $150/day is more like it. If it gives you any idea, big five month, 25,000 mile trips I have done down south I have spent $10-15k on. Shorter three-week trips to Baja as cheap as $2500. I like to live somewhat well on the road though so no avocado and tortillas or bananas and peanut butter to live on day after day for me.