"tealboy".....We have a 40' tag axle coach and live in California. We've camped inside all of the parks you listed, with the exception of Acadia. It does require more planning to get a spot. Yellowstone is limited at Fishing Bridge and only has a small percentage of 40' spots. Yosemite has quite a few sites that will hold a 40' coach. Watchman Campground, inside Zion, also has quite a few sites that will take a 40' coach.
We're going to Yellowstone this summer and tried to get a couple of 40' spots a year out and were unsuccessful. I believe they are still rebuilding sections of the campground, limiting 40' spots. Since we were unable to get into Fishing Bridge, we booked at Grizzly, a nice private campground at the west gate of Yellowstone.
Grand Canyon only has one campground inside the park, Trailer Village. I would say most of those sites would take a 40' coach, but is hard to get a site without booking a year in advance. As with Yellowstone, there is a campground about a 1/2 mile outside the south entrance that we've always been able to book.
I listed the above campgrounds to show that if you can't get into the National Park Campground, you can usually get close enough that it's still convenient. We always prefer to get a spot inside the park, but second choice isn't bad.
The issue the last few years is not so much the length of the coach, but the extreme numbers of people camping. More than anytime in the past.