Do your homework.......Check out every single floor for which cabins are available.
We book a Cat E1, standard balconly cabin, on the Explorer of the Seas for April 06.
The cabin it's self is approx. 173 sq ft, but the veranda is about 200 sq ft. A nice touch.
Our cabin is located on the back corner of the ship (deck 7). Corner cabins are usually small rooms, but have very big balconies. We have #7388 with 3 in this room, more than doable. Check out
www.webshots.com, look into the community file and then type in Bonnie Voyager, this lady has some very nice photo that show cabin and balconies on ships. If you can't find your ship, then in same community file, type in your ships name. You will indeed find lots of photo's of it. This site is very useful to us in our cabin selections. Always find photos of almost every cruise line and ship.
If money is not important and kids ages are not young, try 2 rooms. 1 balcony and 1 inside. We have a family of 5, thats what we have to do. We put 2 boys (14 & 13) in the inside and we and 10 yr old take the balcony. Always take an inside cabin right next door. It's great, more space per person and 2 bathrooms. Our 7 night Eastern caribbean cruise for 5 ( 2 rooms) cost us $5900.00 for everything. Not too bad.
Hope this helps and you find a good solution. Just keep looking. RCI is a good company, once you make a deposit and find a room, you can switch it whenever you'd like to another room. Also if balconies looks bigger on the floor plan, it will be bigger in life.