There is a possibility I'll be living in Puerto Ayora, Santa Cruz Island Galapagos next year. I was there this past summer and my tour guide mentioned (I can't remember which island of course) that there are established routes on one of the accessible islands. Does anyone know anything about this??? After a quick google search I can't find a thing.
You'd need special permission from the Galapagos National Park Service. The climb itself is sort of like a desert tower with bird droppings! You'll like Puerto Ayora. My wife I lived there on and off from 1977 through 2004.
Treat the place like a wilderness and leave no trace - especially bolts!