You can hike from one end of Isla del Sol to the other in a few hours. Each time you come to a new community, you have to pay an entrance fee to walk on their land. We found this written on the trail somewhere along the way.
Hey friend
Pay 5bs
I will wait for you there
If you haven’t paid I will kill you with a shotgun and bury you
Pay here
Strolling South America 
Nice. Doesn’t really leave you with many options!