I had the same thoughts as you with regard to painting the wheels, adding trim rings and chrome lug nuts, but I never really found the pieces I wanted to make it look good. The lug nuts were the hardest to find. I have removed all of the valve extensions and replaced the original simulators with
Eagle Flying simulators. They look good and have a different kind of clipping mechanism to hold them on the wheel. Rather than a few clips rivetted to the simulator, these have stainless steel clips all the way around the wheel that are part of the wheel cover. To check and air the rears, I remove the simulators and use a dual chuck. I lost one of the original rear simulators on a trip. The clips became weak and out of shape from being removed and reinstalled for tire rotations and balancing. The new ones are holding on tight with no problems so far.