Hi Lisa!
to the DIS!
We did a 3 nights land/4nights sea package in 2001. Beware! After cruising on a
DCL ship, you will be spoiled and no other cruiseline will compare! Since then we've cruised 2 more times with Disney.
Booking A Package or Separate?
The first thing that I would point out is that if you book a land/sea package, your resort room will be tied to the level of stateroom that you book. IOW, if you book a category 12 cabin (the least expensive), then you will be have your choice of value resorts. If you choose a category 5 (outside stateroom w/ verrandah), you will be given your choice of deluxe resorts. So what happens if you want to stay in a deluxe resort but get a cat 12 cabin? You need to book them separately.
Booking separately also gives you the flexibility to choose whether to get a room-only reservation or a package. And you can take advantage of any discounts that are available to you that would not be factored into a land/sea package. If someone in your group has an AP (annual pass), then they can get rooms at a discount. Or there might be a AAA rate available for your choice of resort.
Tickets are always more expensive when purchased thru Disney. There are a number of reputable ticketbrokers who sell for less. The bigger discounts will be for the tickets with more days and features, but you could save a significant amount over the cost of 9 5-day passes purchased as a part of a package.
To TA or Not to TA?
I would definitely book the cruise thru a TA. They can offer incentives like stateroom credits - sometimes as much as $200/stateroom! You won't get this by booking directly thru Disney. Try to use a TA that specializes in Disney, like DreamsUnlimted. They will be able to help you make the right decision for your group b/c Disney is all that they do.
The earlier that you book, the better the prices. My last cruise went up over $1000 between the time that I booked and the time that we set sail! Booking early also will allow you to pick your cabins, rather than have Disney assign them to you randomly. If being near each other and on the same deck (and especially connecting cabins) is important to you, booking early is key. And if you want the main (early) seating for dinner (essential if you have little ones), then definitely book early. We booked in March 2005 for August 2006 and we were waitlisted for the main seating!
How Do I Get There From Here?
I've had lousy luck when I allowed any TA to book my airfare. They always take the cheapest way, which can involve routing me thru another city. The last time, we flew from Philly to Dulles on a prop plane in order to catch a flight to Orlando. Pretty stupid when you consider that there are numerous direct flights between here and MCO plus several others that connect thru Charlotte or Atlanta via jets. Who wants to start and end their vacation taking a commuter flight when you live near a major airport?!!! Book your own air transportation. You'll be able to choose your flight times, which can mean the difference between arriving early and enjoying 4 days at WDW and getting in late with only 3 days to play.
On the ground, take Disney's Magical Express to your resort. It's free to anyone staying onsite. To make the resort--> port --> airport trips, consider getting a a limo service with a van. It will be cheaper than going with Disney's transportation for 9 people. You can schedule the van pick up for whatever time you choose to leave your resort the morning of your cruise, instead of waiting for the Disney bus to pick you up. And heading to the airport, you won't have to worry about dropping everyone else off at their terminal before getting to yours. Your driver won't have any other passengers but you.
There are a lot of helpful people on the
Disney Cruiseline Forum . They can walk you thru the steps to booking your cruise vacation for the best possible price. Good luck!
If you can't find one, PM me and I will reccomend one. 
