I just got back from my first trip to Cabo, last week.
Yep, Cabo San Lucas is deserty.
Ocean, beach, desert, and a couple miles away, mountains.
The whole area is pretty new. As far as I could tell, it pretty much exists just because of the tourist trade. If you are outside of town, most of the places looked like big resorts, with lots of beach front and pools, lots of space. In town, it was more like city hotels, with the beach down the block. One big plus. Because it’s a desert, hotels of any size are required to put in their own desalinization plants, to make fresh water. The water from the pipes in our hotel was drinkable. I used it for 4 days, and absolutely no problems with it. In town, around the marina, are a whole bunch of nice restaurants and shops. If you want to see Mexico, this is almost more like Disney then “native” Mexico. Nice, but very tourist driven.
If you like deep sea fishing or golf, the Cabo San Lucas area has lots of both. Mid-Jan through Mid March is great whale watching. (We could see them from the hotel.) There are lots of 2-4hr boat charters available, fishing, diving, snorkling, glass bottom boats, whale watching and just plain sailing. We also saw ads for ATV trips and horse riding.
If you are willing to sit through someone’s timeshare sales presentation, you can get a free activity from them. We meet people down there who had scheduled 3 of those during their trip, even though they already owned a timeshare somewhere else. Don’t worry about finding these. They will be waiting to talk to you when you get off the plane. Not overly pushy, but definately there.