The only thing wrong with a 4 day is that it isn't 7 days long!
You can save significant $ by booking land and sea separately, but it is totally up to the decisions YOU make. For instance, I see that you are staying at a value resort. The value resorts aren't on the cruise packages. SO, if you want to book separately and stay at a value resort (instead of the moderate on the package), you will save $. The packages all include the Ultimate Park Hopper Pass. That pass starts the minute you check in and ends the day you check out. It includes EVERYTHING. The price is roughly based on park admission for every day of the trip, including arrival and departure day (you can find the cost of this pass on the WDW website for your specific number of days). SO...your package includes this cost.
Will you use all the features of this pass? Will you go to the water parks? Pleasure Island? Will you go to a theme park on the day you arrive and on the day you depart? If the answer to ANY of these questions is NO, you might save significant money on Park Hopper Plus passes. Another good thing is that PHP passes never expire...so if you have any left over days, you can use them on your next trip.
For instance, we normally arrive about 3 pm. Sure, I wish I could get there earlier, but with flight schedules, Mears, etc....that's reality. We check in at the resort, then hit the pool....then we do a character dinner at Chef Mickey's or at the 1901 Park Fare. SO, that doesn't use park admission but still gives DD the character experience. Thus, not a park day, the park admission $ saved. Also on departure day, we schedule a character breakfast in a resort before leaving for the ship. Again, no park admission, $ saved. With PHP passes, you still have limited admissions to water parks or Pleasure Island, just not unlimited times. The way we use them, it comes out a lot cheaper. You might even want to look at this option for your earlier trip.
Things to consider....if you do
trip insurance, you may want to do it privately if you book separately. If you purchase thru
DCL, it will only cover the portion of the trip that you book with them. If you do it privately, it can be cheaper and will cover the entire trip. You can add DCL transfers to your trip (no matter how you book), or you could use a private limo. The break even point for a private limo is generally 3 people. For 2, DCL transfers will be cheaper. For 4, private is cheaper. For 3, usually it is about the same.....DCL busses don't run from the Value resorts to the port. The bellman will get you to Animal Kingdom lodge to catch the cruise bus if you decide on this route.
This is probably way more info than you wanted this early.....Keep asking questions.