A land/sea combo package should include entry to the parks for your stay....check with your TA.
Now, did you book both parts separately and only got a room rate at the parks??
I do know food is not included on the land portion of a land and sea package so I think it is a much better value to do 3 days land/4 day sea because you are getting 4 days of food on the ship. You only have to pay for food for your 3 day land.
I you do the 4 day land and 3 day sea you have to pay for 4 days of food on land.
MJ