We were on the Golden Princess, which is the same as the Grand, just newer. We were on the Caribe deck (check out my review at http://www.cruisereviews.com/Princes...nPrincess2.htm
) - room C510. Ask your travel agent for the ones that have the bigger balconies. Ours was one of those. Also, the deck below us (Dolphin) was 100% non-private, where ours was 50/50. i think our room was a BA class, but you can check that out in the brochure.
After reading several postings from vacationers on this site, it seems that the majority would not recommend booking through a website. Find a local travel agent, book your own airfare (not through the cruiseline) and buy 3rd party travel insurance (not through the cruiseline). Tom Ogg has a great write-up on travel insurance at http://www.cruisereviews.com/Insurance.htm
Good luck and ask away if you have any more questions!