Overall, this has nice amenities and provides a nice stay while visiting the South Rim. It has all the hookups one could need and is close to the stores. The people were helpful and the sites were functional. All locations looked relatively level but will likely need leveling devices. Our site, F28, was level, had a few trees, a charcoal BBQ stand but no fire ring. We were lucky to get an end space, allowing a little more room. But most sites are right on top of each other with no trees or foliage in between. There is a bus stop at the entrance to Trailer Village, allowing one to keep their RV parked and be able to enjoy the entire park. The only real negative was the expense, but that is to be expected in such a highly visited location. It is unlikely you can get in without reservations.
This is a nice campground, but might be difficult to find the right site for an RV. We stayed in space 52 on Loop B, which turned out to be great for our 24' RV. I would be surprised if a 40' could get in as is listed on recreation.gov shows. It is at the top of a hill with a slope downward away from the campsite. It is quite open and private away from the site. Overall, I liked Loop B better than Loop A but Loop B had fewer RV acceptable sites (which actually is probably why it is nicer). The site might get a little muddy during rain. It has a table and fire-ring with adjustable grate. The ground was quite level and I didn't need to adjust our RV to get a good level. The buses were not running at the time we visited so we had to drive our RV through the park. It wasn't too bad but slow.
What a great campground. We really enjoyed it. Beautiful scenery, people were respectful and the trees kept things cooler. On the negative, the first come first served access makes it difficult and frustrating to actually get a spot. The place fills by 9 AM quite often. We stayed at Watchman for one night (could only get one night) and moved to South early the next morning. At 9 AM, only 3 spots had not yet been reserved. But we got a nice pull-through and generous sized site. It was a bit of walk to the Visitor's center to catch the bus, but not too bad. So we actually like South better than Watchman. This campground has it's own dump station and water spigot just outside the campground. I imagine anyone, camping or not, could use them.
Overall, this is a nice campground with minimal services for the RV. I would stay there again. We actually enjoyed South Campground at Zion much better. But it is first come, first served and does not offer power. I like the ability to know I have a spot when reserving a site at Watchman. Some of the positives of this campground were the pure beauty of the surrounding cliffs and the river itself. We stayed in B048R, right on the river. It is a small site but large compared to other campgrounds. This site had trees and shade. On the negative side, tent campers were taking the RV pull through sites, which were quite a bit bigger. And in spring, when we stayed, there is an invasion of caterpillars that devour all the leaves, resulting in a complete mess including a constant rain of caterpillar droppings so intense one could not eat outside. The river was also flowing very strongly and was quite loud (this can be good or bad, depending on your taste).
We enjoyed staying at Wahweap Lower Campground. It was a nice location, had a nice view of the lake, our spot, A20, was close to level, had a fire ring and table, and the drive was recently sealed. The sewer and electrical hookups were clean and modern. On the negatives, the registration closes very early (5 PM, but they put your reservation and site on the door for late check in), the bathrooms were not very clean, the recycling collection point was full and overflowing, and summers will be hot with very little shade and developed landscaping. I would not hesitate staying there again.