our january sunday - the 6th - wasn't toooo bad but the next saturday got extremely busy extremely quickly.
it sounds like a good idea to have an itinerary but what we have found to work is being a little bit more casual - if we pass a ride with hardly any line we get on it - if we have fastpasses we can use we use them to come back later etc. btw if you get two sets of tickets your saturday ones may work for fastpasses on sunday.
there are boards in both parks to give you an idea of the wait times.
i always get a timetable and work out which shows we should go to and work around that a bit. the shows are a good chance to have a picnic and a rest, you see.
you likely will not get to do everything in two days if those days are on a weekend. so relax and don't feel like you have to do everything, is my advice.
if you have a character meal somewhere like inventions after the park closes on the saturday you won't have to worry about meeting characters in the park.
if it does happen it will be a nice surprise.
for us the nice surprises happen in disney studios in the courtyard.
also we eat huge breakfasts so we don't have to have a table service lunch and lose out on park time sometimes.
croissants filled with cheese and ham mainly.
oh how the other guests look on with disdain!
my mum should never have taken me to dunkin doughnuts.