Salt Lake City has a need for more good places.
We have family living just south of SLC (in Sandy), visited many times, and we have always stayed at Mountain Shadows RV Park in Draper.
The quality of the sites varies widely; some are great and some are a pain for a large MH. Understand you have a Roadtrek, (class B?). You would probably not have a problem.
We have always gotten good service. Staff is first rate.
It is close to the interstate (on a dead end road) but the noise has not bothered us. Have never felt unsafe anywhere in the SLC area.
The KOA in town is a good park, but not convenient for our purposes.