So fun. As your little guys grows and gets older, you will see his personality develop and you can plan more of what will work for you. You will see if he is a kid that you can go at your pace and you can just plop him in the stroller for naps and bedtime, or will be be a kid that must have his 2 hour nap in his bed, or be in bed at a certain time every night or melt down. This will certainly be a factor in
MNSSHP. You will have more of an idea of whether he will love or hate characters, and if he in general is a good travel baby or not.
We LOVE CRS. They have a great pool and a super fun huge sand play area that will be great if one parent does not want to do parks while you are in meetings. The bus service there is top notch; better than deluxe we have stayed at.
MK is going to be the funnest park to enjoy with your little guy, but he will enjoy any of the parks and just be happy to hang out with his parents. We do love AK, but if choosing one more park beside MK for a toddlers, I would choose Epcot. My boys preferred it to AK, and there is so much for little ones that you don't think about. The living sea with Nemo, Living with the Land boat ride, Ellen's energy ride, Space Ship Earth, the performers in WS, and my little guys true delight, the light up side walks.
22 months in in general, a really fun age. Walking and starting to talk a bit more, but mostly not to that negative 2 year old behavior quite yet. He's FREE in the parks and Buffets are FREE and basically he can eat off your plate for other meals so that mean it cost nothing to take him, yet he will have a blast.
As you head toward 22 months, think about the trip as you might make transitions in his life....that is often an age of not a lot of change but as all parents do things different, consider the trip when you take the passie, the bottle, transition to a bed, toilet train etc, and if you are close to the trip, postpone til after. We took bottle about 22 months (right after a trip) and passie about two. Same goes for weaning if you nurse. Those comfort items can be a huge help when traveling.
Consider waiting for his first haircut at main street barber shop too. Have fun planning and watch for cut Mickey outfit at the end of summer sales going on now. October is still very much shorts weather for the most part!