To figure out what you have, pull one of the chrome covers off.
Tap each of the 10 lug nuts. Two will sound solid and the other 8 will sound tinny.
With a pair of pliars pull the chrome caps off the two that sounded solid. You will find two large nuts holding the small center on.
The nuts on the drivers side of the coach are backwards thread and the passenger side is normal rotation. IE: on passenger side you turn the nut CCW to loosen.
Now with the outer cover removed, remove the rest of the chrome simulator.
Next to the valve stem will be the maker of the wheel. Being a Safari, it probably will be Accuride wheels. And probably be wheel #27403
Now go to the wheel maker web site and look up wheel part number. That will give you the diam, width of the wheel and the wheel offset and bolt pattern.
Most of the older Safari's had 9R22.5 tires mounted on Accuride #27403 wheels
Accuride 27403 Info
If this is your wheel, you can get the info and then start your search for alum wheels the correct size.
96 3540 Safari