we were in DL last October during the Utah and Arizona invasion,

and ate at the CC two different times...once for lunch and once for dinner and had no reservations either time...max wait was about 20 minutes.
This is at a time when the park entrance was closed a couple of days because of extremely high numbers of visitors...
we sat at a nice shaded table and watched the parade from there.

It is all when you go. Try to eat a little before or a little after the majority of folks eat and you can get in just about anywhere in the parks. Eating at the parks is just like knowing when to go on which rides, and how to use fast passes...if you pay attention and think about what you are doing, the crowds are never a problem...
Only eating establishment we have ever had reservations for is BB.
The rest of the time we just decide what we would like to eat on the fly and find a spot accordingly.