Keep in mind that Cabo is usually 1/2 day. Allowing for time to get everyone on an off the ship, it is a very short stop. We used to do horseback riding in PV and Mazatlan, but the ships don't offer that anymore. Other than that, just be cautious about trying to do anything on your own that involved motorized vehicles. Hubby almost got killed parasailing from El Cid in Mazatlan.
For what is offered now, I would go to the cruise line website. Even if you decide to do your own, it will at least give you an idea of what is available. Happy Cruising!