Disney's website does not allow you to book travel. however, after you do book travel and have your flight information, you can input that data onto their website and it will help you with organizing our itinerary on their website which is completely optional. My girlfriend and I frequent Disney about twice a year an of course we try to do it in a cost effective way based around what we like to do. So far some of the best tips I can give you are as follows.
Try to find cheap flights around the times your able to go. Remember the more flexible you are about going the less you'll pay for flights. Generally flying out in the middle of the week is cheaper, make sure to check the flexible dates option on south west's website. In addition to that, Often South West will offer 50,000 flight points for getting their Visa. This is huge, it's about $650 in flight points and we were able to get there back from Buffalo for about 29k points.
Allegaint charges an arm and a leg for luggage, steer clear, they do not fly into Orlando and you can't use the magical express.
Try to utilizing their promotions/special offers for cheaper rooms. It's generally an automatic thing when your researching rooms during your cheap flight times. You'll see the discounted pricing.
https://disneyworld.disney.go.com/special-offers/
Staying on site eliminates the need for any vehicle rental because of the magical express to and from MCO and also Disney busing will take you to and from any Disney location.
If it's just two of you, don't bother with the meal plan unless your plan on not eating appetizers, having adult beverages, and want a bunch of deserts. Generally we know at this point where and what we like to eat so we have figured out the the meal plan is actually a little more expensive for us based on what we like to do! Generally we will Snack all day and have a sit down dinner. No need for Huge breakfasts for quick service meals that fill you up before a late or early dinner. Do so research and check out how much the dining plan is for you and if it viable based on what your going to eat. Remember the dining plan is only good for the number of nights your staying. If your stretching out your last day, your food wont be covered on your last day unless you have some leftover unused credits.
Mail yourself food don't pay for a 5th bag if you want to save on flight and food costs. Once you know where your staying, mail yourself something ahead of time and you can pick it up at the lobby of your resort.
Don't use park hoppers. Do a park a day because your fast pass+ attraction reservations are only good for one park per day. You cannot book across parks in advance in the same day.
Don't try to experience everything in one trip it's not going to happen. have an idea about what you want to see during this trip. Riding Rides, Seeing Parades, Trying Cuisine, Seeing Fireworks, Visiting Resorts. Found out what you want to do it's all exciting!