Jenny,
I am so sorry to hear you missed your flight. I hope you do indeed get to take that cruise. Jim and I took that exact cruise in November, aboard the Carnival Pride. The wheelchair accessible rooms are large, the ship very wheelchair friendly. There are only a few areas that you cannot access with a wheelchair.
I do have some tips for you when you do sail, which I hope you are able to do soon! First, there are wheelchair vans at Puerto Vallarta and Mazatlan, we rented one for the day in both ports. Ask the driver to go slowly, as the bouncing was uncomfortable. Also, Mexico is not well designed for wheelchairs, if the driver does stop to let you out, plan your "walk" well. The other thing to take note of, at certain tide points the ramps are not accessible onto the ship. We had gone out for the day in Mazatlan, imagine our surprise when we returned to the ship to find a 6 inch "step" that the wheelchair couldn't clear. The ships crew told us we would have to wait 2 hours for tide to come back up. We (meaning other guests and I) managed to find a plank of wood and make a makeshift ramp and get on board anyway, but it was a huge hassle and very hot.
Also, it is indeed very warm in Mexico, cool water is hard to come by, and Jim was very hot. I brought a large container of cold water, and continually wetted his hair and shirt on our outtings.
You won't be able to get off at Cabo san Lucas, as they use tenders. However, having most people off the ship, we enjoyed a relaxing day by the pool nearly alone.
The last "issue" was that the stateroom balcony is not wheelchair accessible. However, the door is very wide, and Jim was able to sit by the door and enjoy the view.
I hope you get to go soon. It was overall a very pleasant experience. I hope you enjoy! And very sorry you didn't get to make it on the first run, but as you said, you now know precisely what to expect, and next time should go very smoothly. Might not be a bad idea to arrive 1 day early, just in case?!
Andrea - wife of Pals Jim