I have heard it is cheaper to book them seperately, but we booked the 3 night land/4 sea package (then seperately added on 3 nights to the land package on our own.) We were very happy that we booked the package for a few reasons....
-we were first time cruisers and wanted the least amount of "wish we would have know that" kind of situations with the check in etc.
-all the details are taken care of....the check in for the cruise at the resort (no waiting in lines at the terminal), the transportation, etc.
-our baggage was taken care of the morning of the cruise, as we headed off to AK to enjoy a morning there before getting on the
DCL busses.
-Plus, we booked a Cat 6 stateroom, which automatically put us in a deluxe resort for the land. If we booked seperately, I am not sure we would have shelled out to stay in a deluxe, so it was an added bonus!
You may want to go to the Disney web site and get some ideas of what you may be looking at for ballpark prices for both situations, then get a quote from DU. We figure the few dollars we paid more for booking the package saved us a headache or two and lots of extra work booking transportation and such!
Excellent choice for a Honeymoon, may I add! It's what we did for ours!!!