Just giving you an idea, We did 3 days of MK 2 weeks ago with Child swap and we did it all with time to spare. DD6 was in riding heaven (doing each ride 2 times atleast), but DS2 had to stay back.
I would say given you have just a 3 yr old, in 3 days you will not have a single thing left to do (that you would want to do anyway)
First day - you may not want to rope drop... and even if you do.... just meander in .... take it all slowly. Save the rope drop for other days.
What is your plan for the rides that DS cannot ride ? Single rider ?
The best part of Fantasy Land is that your DS can go wherever you want to take him
- meaning everything !!
We did it in sections so that we do not walk too much. We finished Tomorrow land in 3 hours one day. We did Adventure and Frontier the other spilling over to Liberty Sq. One day for Fantasy Land and then everything else fell into place on each of the days here and there. Most time consuming were the meet and greets.... if only my DD was not into it... sigh !!
Hit all the shows, they are really fun and as someone said, please please please take a mid day break and get your DS to sleep, and the break is for you also, not just for the kids. Kids are well rested and I have very nice memories of my DS running around the carousel at 10 pm.
I think you will have an awesome time.