I was asked to comment on changing wheels.
For most RV owners the wheels that came with the RV when new should work just fine.
If you are running the original size tire and have confirmed you do not need to increase the Load Range of your tires to carry more load with a higher inflation there is no reason to change your wheels, unless you have damaged one.
Now if you want to change the look of your unit and change to special chrome or aluminum wheels, then there are a number of things you need to consider.
What is the maximum load capacity of the new wheels?
What is the rated inflation of the new wheels?
Are they the same width and flange contour?
This means the official size is identical, such as 16x7J - Note the letter is the shape of the area that contacts the tire. You should not change letters such as changing from a J to a K. One is not better than the other but tires are designed for a specific flange shape.
Finally, If you run duals then the "offset" dimension is very important. If you go smaller your tires may rub which could cause a problem.
All of the dimensions and ratings need to be stamped into the wheel or in writing from the manufacturer. I strongly urge you not to just take the word of the person selling the wheels.
If you think you need to change the wheels because you are changing tire size or rating to carry more load, you need to work closely with the supplier to be sure you are not overloading the axle, springs or other suspension components and the dimensions of the new wheels will properly fit the hub and bolts and the offset will not allow the tires to rub.
Tires intended for dual application have specified clearance called "Dual Spacing", so be sure to confirm that dimension from the tire manufacturer before you go wheel shopping.