I can only comment on the RV park we used at Zion
We stayed at Zion Canyon (which is adjacent to the Quality Inn) for several days two summers ago.
We were there because we could not get into Watchman.
The campground has fantastic views of the mountains, but then of course, everything there does.
It was pretty quiet but fairly busy.
One benefit of staying there is that the bus to get into the park stops within a block, very convenient.
We would stay there again.
Most of these campgrounds near major parks are really just places to stay that facilitate exploring the park.
I would not consider any of these RV parks as peaceful, wooded, secluded, highly desirable places.
We came there from Lake Powell, then went to Las Vegas to drop of family, continuing on to Arches.
Now !!!!!! -- you must hike Angel's Landing -- -we are older hikers so only went to the notch just before the narrow ridge to the top.
Son and his family went all the way. Fantastic trip, but a decent amount of hikers.
Look at the trail on Youtube. Amazing
good luck -- Dale