Right off the bat, the family suite is very very pricey. You can get much lower cabin rates, and they are still very nice cabins (ones with a veranda) you can also get much much lower rates for a room with a "navigators veranda" - which oddly enough is not as nice as a normal vernada, you would think a navagator would get something better. Then the price really drops for porthole rooms or inside rooms.
You have to also remember that just about all your food, and most of your entertainment is paid for.
I would not do the bus transfers ($70 a person) but would either rent a car or better yet, book a limo/car service. Especially with a group of five, you are looking at $350 total for a bus, you can easily get a limo for that.
The nice thing about car service (or a rental) is you can get there early. That way you can enjoy the ship while it is in port. Pools (and bars) are open, as are some buffets. You can also get on early and book the spa appointments (and the open air cabana massages on the adult only beach) if you want. Slots for those fill up very quickly. If you take Disney transport, it gets you there whenever it gets you there. It may pick up from multiple resorts and get you there pretty late in the afternoon. You are not going to miss the ship
but you may have 2-3 hours less "playtime" on board then people who drove or took a car service.
-dave