For a map I ordered topos from OmniMap. The two 1:50,000 sheets that covered the hike are:
64-435134442 $18.95 Costa Rica 1:50K topo 3444-2 San Isidro
64-435135443 $18.95 Costa Rica 1:50K topo 3544-3 Durika
The sheets have a 1 Km grid but the coordinates don’t match UTM. I was able to compare some UTM coordinates I found online to the map coordinates and come up with a fudge factor. I then labeled the map with my fudged coordinates. The yellow highlighter line is roughly transferred from this map supplied by mvanderbilt
https://www.summitpost.org/images/original/646591.jpg