The problems are inherent to all dually wheel installations.
The pros use dually chucks and gauges, with appropriate valve stems. They don't usually have the option of speciality stems or extensions to make the job easier, all wheels have to be interchangeable. Wheel covers or "simulators" just make the problem more difficult. Edges of the openings are almost razor sharp, ouch!\ After the first few months pulling off covers to check pressure, I pulled them off permanently and put them in storage.
There are a variety of custom solutions, extensions and custom-built long stems. Anything much longer than a 1-3 inch stem needs support, usually included in the package. But for a RV, with tires rotting faster than you wear them out, no interchangeability needed, it is an easy way out, and you can still use the wheel covers.
