There are several threads that discuss rental car and Cabo activities.
In February there will be all sorts of whale trips. Also Whale Sharks up at La Paz. All activities will pick you up where you are staying and return you after the activities. There are snorkel trips. The snorkel trips take you to Chileno or Santa Maria. You can drive to these two locations. Also most commercial snorkel trips now require you to wear a flotation device. Kind of hard to go under the water while wearing a flotation device. We take our own snorkel gear. We normally drive to these beaches arriving about 8am. No wind, no waves, no crowds. When all the snorkel boats arrive we get out and eat the meal we brought.There are bathrooms but I recommend taking your own toilet paper. You will need one or two beach umbrellas. You can buy these at many stores. We wear skins when we are at the Beach on on the water. Patti wears a 2 piece one. I wear one that goes from my wrists to my ankles and all parts in between. But remember to keep your feet in the shade or heavy with sun screen. There are several options to swim with the Dolphins. Most are in large pools like Sea World. We prefer the one in the Harbour at San Jose del Cabo. There is riding camels, Zip lining, desert tours in ATV's, etc, etc.
We always rent a car in Cabo. There are some rental firms that advertise less than $10 per day. But then they will not rent you the car unless you pay for Insurance. Which will cost you $300 - $500 per week. You are reimbursing the Rental Company for Insurance they are required to already have by Mexican Law. We normally rent online from Hertz before we go. You decline the Insurance and they move on with the Rental. I recently talked to an Ex Pat. His car insurance for the Year with total coverage is $500 per year. So think of the profit the Insurance companies are making on having the tourist pay for car insurance.