This is basically what we do.....we like the 7 day cruise, but want to add some WDW time too. There are great advantages in doing it this way.
First, the transportation. It sounds like you are flying into MCO. OK, for your resort stay, you use Magical Express. This is a currently free service for people staying at any WDW resort. When you book your resort, or any time later till you leave, you can give them your flight info. Magical Express will send you luggage tags (similar to the way the cruise does). You fly into MCO, go the the Magical Express desk, and they direct you to the line for the bus for your resort. IF you don't get the luggage tags, no big deal--the desk can take care of everything for you. You can purchase
DCL transfers from your hotel to the port. If you are not staying at a resort serviced by the DCL busses, the bellman will take you to the nearest resort with DCL service. You also purchase transfers for after your cruise back to MCO.
As I write this, I realize that this is based on going to WDW first. This is the way we like to do it. First, the parks are a lot of walking, and are "work" for the mom. The cruise is total relaxation. Secondly, kiddos get used to the service on the ship--dial room service and get a Mickey Bar or Rice Krispies any time you'd like.....someone to pick up after you and get you ANYTHING you'd like for dinner, etc. In fact, I've frequently come home and said, "Do I look like Micho? Then get up and get it yourself." It is easier with the kids to re-enter the "real world" from the cruise than to do cruise to park (still not their real world).
MCO to Port Canaveral is about 45 minutes. MCO to WDW is about 20 minutes. WDW to Port is about an hour.
Other advantages...by booking separately, you can choose a different level of resort than would be attached to your cruise cabin (if you'd like). For instance, you might want a cat 6 on the ship in order to have a verandah, but be very happy in a value resort at WDW. In addition, you can take advantage of WDW specials--like right now, they are having a free dining plan with resort stays. They frequently have specials on the hotel rates.
The things to consider....you will need to do
trip insurance privately (not thru DCL). If you insure thru DCL, it will cover only the cruise part of the trip. So, you buy private insurance that will cover all parts of the trip. Secondly, if you do your air thru DCL (not usually a good idea anyhow due to cost), your WDW stay will be considered an "air deviation" and have an extra cost of $50 per person. If you do your air privately, there's no problem.
If you have other questions, these boards are the place to ask....lots of experience here!