My family of 4 sailed on the Rhapsody in June 2005. We had connecting oceanview rooms on Deck 4. We booked in April 2005 for the June cruise and paid $1250 pp, so the fare you're seeing now is great, however, you are going when all the kids are back in school while we went during the peak of summer cruising season (and we paid the price). This was our first cruise in over 20 years (had previously sailed with Carnival on two of their older ships that are not even in service anymore). We had a wonderful time, our teenager daughters had a blast. We loved it so much we are booked on the new Freedom of the Seas next July. The Rhapsody is a fine ship, very classy and more upscale than what I've heard about Carnival, even their newer ships.
September seems to be the most active month for hurricanes, especially in the Gulf of Mexico. Keep that in mind! We sailed in late June. We were very lucky. Our cruise week seemed to fall in between 2 major storms. We had smooth seas the entire time. It was wonderful. We especially liked to lie on the top deck at night under the stars and watch for shooting stars.
Also, the ship (and I'm sure all the others, too) are cash-free. The only time you need cash on board is in the casino. When you check in at the pier, you'll need a credit card to cover your incidentals (much like when you check into a hotel). All your drinks and purchases on board are charged to your room and you'll get a bill at the end of the cruise. Even your gratuities can be charged to your room. We didn't realize how much we were spending, especially when all 4 of us were "charging things to our room." It adds up! Let's see ... the drink of the day (several times), bingo, pictures, t-shirts, Ben & Jerry's ... you get the picture.
EZ Cruise parking is the way to go in Galveston. Google-search them and if you pay on-line in advance they give you a discount. Their parking lot is only a block away from the pier.
Have a great time!