Our travel destinations are typically national parks & monuments, national forests & bureau of land management, and other such federal & state government owned lands. Our rig is less than 24 feet (23'-8") and we never have any trouble in campgrounds as long as the parking pad is not exceptionally steep. It does seem that a rig a few feet longer will do just as well 98% of the time. A 30 footer would be a stretch, but they are seen about. I think they are more limited with sight-seeing pull-offs and selecting a campsite.
We really do love our rig but admittedly it can be a bit large for a few situations. We owned a different motor home for 24 years that was only 17.5 feet long, 6 inches shorter than our 1971 Delta-88. When our newer rig length becomes an issue, my wife will sometimes say "Our old Mirage wouldn't have this problem" of which my reply is "Yes Dear, I know".