Hi, Michelle!
Not to worry. While there will most likely be some crowds during your visit to Walt Disney World (depending on the time of year) there are lots of ways to avoid letting those crowds interfere with your plans.
First, take a look at this fantastic post on
traveling with little ones in Walt Disney World. There are lots of links and tips for families with the youngest Guests, so really allow yourself some time to investigate each one.
Next, be sure to take advantage of the
Baby Care Centers in each of the 4 theme parks. You'll find so many wonderful surprises that are geared to help make a trip to WDW so much less complicated, even if your little prince is only 21 months old!
Regarding your schedule, allow for enough time for sleep and anticipate when he'll be hungry. After naptime, head back to the parks or spend some time at your resort pool. Grab a laid-back bite to eat at Downtown Disney. Pair a busy day with a relaxing day to let him recharge those toddler batteries.
Also, always have a cool beverage and a snack on hand, as these two can work wonders when you're in a line for a character meet or a great attraction but somebody's tummy isn't cooperating. If you sit down to eat at a Table Service location, bring something to occupy him while you finish your meal (figures, washable crayons, etc.) We also brought bagged cereal or a fruit and cereal bar for the little ones to munch on as we waited for our meals to be served. On that note, we also really loved the buffet meals such as Chef Mickey's and The Crystal Palace. Once your server takes your drink order, head right to the food; no waiting!
Send more questions as you think of them, Michelle. We love to help!