I think I'll scratch the idea I had of moving to South Carolina to be with my daughter more often.
Oklahoma stopped collecting personal property tax (at state level) on motor vehicles registered for highway use about 15 years ago. While personal property tax is an county option for other types, my county decided to stop collecting it when the appraiser demonstrated that collection costs were exceeding revenue.
You need may to consult with a local lawyer. It is quite possible that personal property tax in your state includes all taxable personal property owned, regardless of storage location.