Should you cruise again, I would recommend a Holland America Line instead of Royal Caribbean for you.
Holland America Line has worked to make their ships (and many excursions) as accessible as possible.
However, for your current cruise I can't stress this enough... Make sure you and/or your travel agent notify the cruise line of your accessibility requirements. The cruise line is in the best position to tell you what can and can't be accomodated onboard as well as give you recommendations as to the type of wheel chair to bring and what their excursions can accomodate.
In addition if the line knows that you have accessible requirements that probably will play into things like your seating assignment at dinner and such...