We enjoy both DL and WDW. The first thing that you need to realize is that there is a reason they are called "land" and "world". DL is just a little easily walkable "land" while WDW is the whole huge world! As couple of examples of the size- 1) walking from 1 end of the World Showcase to the other end in Epcot is 1.2 miles (and that is just half of the park); 2) It will take you about 20 minutes by Disney bus to get from the Magic Kingdom park to the Animal Kingdom park.
The best thing you can do is hang out on these boards. You will learn a ton! WDW does have park hopper. We love it and use it, but hopping is very different at WDW than it is at DL. You can't just walk between the parks in 2 minutes. It can take you an hour to get from point A in one park to point B in another park. Hopping is used more for things like 1) Spending a good part of the day at AK, and then wanting to spend the evening at Epcot or MK 2) wanting a specific dinner at Epcot. 3) wanting to go to Spectromagic/ELP at MK, but knowing MK will be more crowded that day, so you spend the day at Epcot and then hop over to MK just for the evening to catch the parade and fireworks, etc.
WDW is like DL in that you can book travel packages or room only through the WDW website. If you want to stay on property, we find the best site to book travel is the WDW website itself. Always check the special offer section as you have to link through that for the best deals. You do not necessarily want to book airfare through WDW. We have found that we can get better travel times and/or cheaper rates booking the airfare ourselves through the airlines.
As far as on-property v. off-property, WDW is very different from DL. WDW doesn't have "good neighbor" type hotels. Unless you have a family size that is too big to work well in the on property rooms without getting crazy expensive, for a DL vet, I would recommend staying on-property. WDW has three levels of resort value, moderate, deluxe. I have never stayed at a bad WDW resort. You can play around online at the WDW website to see the differences in prices, etc. The resort section here is also a good place to get info on the resorts.
If you only plan to go to WDW on your Florida trip and are staying on-property, you do not even need to rent a car, unless you just want to. We haven't had a car for our last several trips. Unlike DL, WDW's Magical Express will take you from the airport to the resort for free (you don't even have to pick up your bags at baggage claim you can use WDW's tags and then they will pick them up for you and deliver to the resort). Once you are at the resort/on Disney property, you can get anywhere else on WDW property by either bus, boat, or monorail. We love not worrying about driving anywhere.
WDW does take more planning than DL/CA. The main issue is that if you want TS (Table service) meals the restaurants start booking at 180 days before your trip, and they can book up fast, especially if they are running a
free dining promotion during your trip dates. If you want TS restaurants you will want to book ADRs (dining reservations) Everytime we go to WDW, at least at one meal (and usually more) as we are waiting for our table we watch multiple people come up and ask if they can get on the "list" or get a table, only to be told the restaurant is booked for the entire day. At MK, you can walk in and see a sign that tells you that ALL TS dining is full for the day. So unless you want to live on CS (counter service) your whole trip, you do want to make some dining reservations as soon as possible. Remember, these can always be changed. There are people on here who book and rebook, over and over again before their trips. It is best to have ADRs for something, then tweak and change from there. (I have been on the phone or on the website while at WDW moving things around when our plans changed during our trip). As far as ADRs, this means that as far as planning, you need to come up with a sort of plan of which parks you want to be in on what days and do from there. Unlike DL, you can make all of your WDW dining reservations on the WDW website. If you can't get something you want, keep trying even multiple times a day as cancellations happen frequently. Persistence pays off (Last year I spent almost 2 months trying for something and finally got it) !! Some of the things you will see booking up the fastest are the Princess meals; other character meals; and Le Cellier. Allears.net is an excellent resource as it has all the restaurants listed with their menus and prices.
As far a picking which days you want to go to which parks, there are services that can help you with that if you don't want to do it on your own. The services give you an idea of which parks are expected to be the most crowded on any given day. The main services are touring plans and Tour Guide Mike. We have used both and we prefer Tour Guide Mike. It is a little more expensive, but we have found it more accurate. Some people around here like to plan every day to the minute- which ride exactly when, etc. That isn't us. We pick a park, schedule one TS there, and then go from there. You do at least need to know the most popular rides so that you can plan your fast passes accordingly (i.e. if you want to ride TSM at DHS, or Soarin at Epcot, you want to be there when the park opens and head directly to get fast passes!).
Another thing is on the WDW side of these boards, you will generally get a lot more responses if you post this type of question on the Theme Parks Attractions and Strategies section instead of the tips section. Theme Parks seems to get the most traffic.
Hope this helps you get started!! Don't panic. It can seem overwhelming when you first start looking at WDW, but once you get into it, you will figure everything out!
