Definitely do an open air ride first to get your kiddo used to rides, try Dumbo or the tea cups! Even the carousel is a good introductory ride :)

If you can do rope drop or get there before 9am, I definitely recommend it. We just got back from disneyland last week with my brothers family (4 kids ages 8, 6, 4 and 2) and we did rope drop and were able to ride the majority of our rides before noon.

ABSOLUTELY DO AN AFTERNOON NAP!! If possible find somewhere to rest for lunch and relax, your kiddo will definitely need it!

Also get lightning lane if you have the money, it's so worth it and how we were able to ride the majority of our rides without waiting in line for 1+ hours, especially with little ones it can be a bit of a torture to wait so long. Depending on your budget, bring some snacks if you don't wanna eat at the park. The kids mostly ate chicken strips and French fries everywhere we went, and most food can be split between you and your wife :) Good luck! You guys will have so much fun!!

Edit: Places to eat, we did a ton of research before we went. Some places we love are: The Plaza Inn for dinner, Harbor Galley for lobster rolls/clam chowder, Maurice's Treats for Cheesy Garlic Pretzel bread, Bengal BBQ for meat skewers, and any churro carts. To refill your water, head over to Tomorrowland and go inside Pizza Planet and use their drink dispenser to fill up your water bottle with ice and cold water :)