It really depends on your tolerance for either standing in line or not doing/seeing/riding the various attractions. If you hate standing in line and don't mind planning your steps in advance by all means shell out the annual fee.
If you’re interested in building your own I would recommend touring plans.com. The interface is pretty easy and it’s useful if you want to get an idea of how much you can realistically do in a day.
If you want to use an existing set of touring plans and go with what they recommend EasyWDW.com has them for free (I think).
That's my absolute favorite time to go! We've been multiple times at that time of year and rarely wait more than 20 minutes (and never more than 30 minutes) for anything.
The most important thing is to show up well before the parks are scheduled to open.
This is how I make my touring plan: look at the cheat sheets at easywdw.com and take out the things that don't interest you. That's your touring plan. As far as timing, plan on 4 attractions in the first hour, 3 in the second hour, and 2 every hour after that.
You can put into the program which rides and shows you’d like to see. You put your FP+ in and any ADRs or breaks. It uses statistical data from previous years to estimate wait times, walking times and will make a plan for you based on how fast you intend to move. It will make a plan for you or tell you what to expect from your own plan.
Back in the “day” it was extremely reliable, since FP+ it’s less reliable. If you know the parks and study wait times on the app you can probably get a good idea for a workable plan. I made a plan recently for my SIL and DGS and it worked fairly well for them.
mydisneyexperience.com shows current wait times for all attractions
as does laughingplace.com (it's free - how do they pay for it I wonder)
I ponied up fifteen bucks for TouringPlans.com - which let me know I wasn't absolutely nuts for thinking I could do most of the parks in 4 days
Also, same day, it can recalculate what you'd like to do on the fly, in just a few sec. If you are not familiar withe the layout of the parks, I highly recommend using it to help build an itinerary, and a walking path. It does those thing for you, and also allows you to customize using your own common sense. The computer cannot use common sense, but it will give you a fantastic starting point to build an itinerary for what you tell it you want to do. For what it is, it's dirt cheap.
They also have a forum just like this one, for questions.
Touring Plans also shows room views/placement at the resorts so you can see the layout and where you might like to stay, and they will fax a room request the week before for you. Also (you can do this with a free account too) the reservation finder is really helpful for dining. While MDE has wait times, the TP Lines app shows expected wait times along with actual, so it gives you more info. so I utilize both.
We used it for an eight day trip. Each day had seriously 30-45 items and it was amazing, seriously it was never off by more than a couple minutes for all eight days. In eight days we waited in line more than fifteen minutes about four times and never more than 30. I thought it was a little eerie how effective it was.
We just returned from 5 days at the parks, during Thanksgiving week, so very busy. I really enjoyed building itineraries with TouringPlans as part of my planning, but to be honest, we didn’t follow them that closely. We mainly used our FP’s and the MDE app’s wait times dictate our days. We ended up doing everything we wanted to (plus extras that we came upon, like the lovely Enchanted Tiki Room and the highly educational Carousel of Progress ). We did have to wait awhile for certain rides, but overall it was not much different than what TouringPlans predicted for the busy holiday week. I did use the Lines app while in the parks to look at the itineraries I built to remind myself on-the-fly what I wanted to do at each park. And I liked how the Lines app allowed me to see at-a-glance what the showtimes were for all the shows I put into my plan. I agree with others to get to the parks early each day to take advantage of calmer early mornings to get rides knocked out. However, for Smugglers Run, we rode it in the early evening this past Wednesday, when wait time went down to 60-70 minutes, instead of 100-180 all morning. I think that’s a ride people really want to do and end up inflating the morning waits. So in my experience, TouringPlans was very helpful for planning and I don’t regret paying for the subscription, even though we ended up not really following the plans.
Oh, one more benefit of TouringPlans I forgot to mention - they have a dining reservation finder that allows you to put in the restaurant, date and timeframe you want, and it checks for reservations for you and texts you when one opens up. This is how we snagged reservations to Oga’s Cantina and Be Our Guest for this past week.