Disney has done away with most of the cruise discounts in favor of early booking savings. The earlier you book your cruise, the more you will save.
After pricing my cruise online at Disney, thru the WDW Travel Co. and with a few TA's, it's been my own experience that the TA's had the best pricing. They can also be of assistance with any question you have regarding ports of call, documentation required and
I would also suggest that you book the land portion of the cruise separately. If you book it as a package, your resort stay will be tied to your cabin preference. In other words, if you book a small, inside cabin on the lower decks, you will have the option of staying at a moderately priced resort (CR, CBR, POR, etc.). If you book an outside cabin with veranda, you will be staying at a deluxe resort (CR, Poly, YC&BC). The AllStar Resorts are not even an option for a cruiser who book the packages.
With the package, your park tickets are included in the price. However, keep in mind that you will probably have very little time to visit the parks on the morning of you cruise departure. Checkin at the port begins at 1 pm (castoff is at 5pm) and the port is an hour's drive from WDW. So, if you're doing the 4-day land/3-day sea package, that 4th day on land will actually be spent traveling from your resort to the port and not at one of the parks.
Another factor to consider is that Disney will allow you to add days on to your land portion of the package but they will not allow you to subtract any. You also must do the land portion of the package first. By booking the land separately, you can save money on accomodations & tickets, set your own schedule and stay at the resort of your choice.