Hi Jacki!
I wish you could have seen the smile on my face as I read your question because in my opinion,
The Plaza Restaurant is Magic Kingdom park's best kept dining secret!
My family eats at The Plaza Restaurant at least once each time we visit Walt Disney World Resort. Like you said, it's a wonderful break from the heat and in a great location right on Main Street, U.S.A. Not to mention the food is delicious and prices are not much more than a meal in a Quick-Service restaurant! For us, it's a no brainer.
My kids also love the desserts that come with the kids' meal. It's hard to beat a delicious ice-cream cone with mickey ears!
You may be able to catch some of the parade depending on where you sit, but I probably wouldn't count on it. Instead, I would plan a later lunch in time to get outside and grab a spot to watch the parade.
Have a wonderful trip, Jacki. I do hope you'll give The Plaza Restaurant a try. It's great!
Happy planning,
Andrea U.