I think the link for WDW vets has been given to you before in other threads -- it gets linked often on this forum. If you haven't read it yet, do so! There is so much helpful information there!
Have a basic strategy and plan down for your trip, especially since you have a family member with special needs. Have a plan A and a plan B, just in case. But (!), then be prepared to throw all your plans to the wind and go with the flow if that's what feels good that day. One of the best plans at DLR is to "let the magic happen!" Don't micromanage the magic right out of your day. You do need a basic plan, but things are pretty flexible here most of the time, and you really don't know ahead of time what might grab your family's fancy. Want to ride the same ride several times in a row? Do it! Draw several characters in a row at Animation Academy? Go for it! Have a relaxing meal, watch a musical act or two, meet some characters, then watch classic cartoons in the Main Street Cinema? The choice is yours to make!
Based on your food budgeting questions in your other post, I'm assuming you won't be making any TS or dining package reservations. But if you want to do so, your window for making these reservations will open up 60 days before your trip dates. You have about a month to think about whether you'd like to do something like this with your family.
I think one of the most important things to do to prepare for your first DLR visit is to make sure to come to the parks with an open mind. WDW is WDW and DLR is DLR. Yes, they are both Disney, but they are different resorts, with different parks, in different states, with different management, different cultures, and different feels, etc. Neither is better or worse, right or wrong. Just different! One of the worst mistakes we hear on this board (and, sadly, we hear it too often) is when guests come to DLR with the deeply ingrained idea that it
has to be WDW 2.0. They have a firm template of WDW that they are determined to force onto DLR. Talk about square pegs into round holes! And when their plan inevitably, and quickly, starts to fall apart, they come here to vent and rant in frustration. Long story, short: don't waste your time ruining your trip this way! Come to DLR with a completely open mind and open heart, ready to see and experience all the magic that is waiting for you here.

It may be just what you expected, or not. It may be the same, similar, or totally different. And it can all be really good!