I checked, Garmin does not provide maps for Central America. Only North America (which of course includes Canada and Mexico), some parts of South America, and quite a few for Europe. Copying any maps from another source to a Garmin GPS unit might be possible, but that is above my paygrade. I suggest doing a Google search to check for "Copying Maps To A Garmin". Google Earth is a HUGE file. Actually, it is a program. I doubt you could get very much of it into a Garmin unit even if it were possible to do so.
"We sleep safe in our beds because rough men stand ready in the night to visit violence on those who would do us harm."