Thank you Detlef for your reply and advice on this. It is hard to believe that out of all the experts here that none have had experience with an item in this condition, or that no other advice is being offered on how to care for it.
I have plenty of experience on working with smaller wooden items and (over the years) have learned that what works for them does not always work the same for larger items. I think that I will leave it "as is" for now as my last experience with having someone else do work for me on a large wooden item turned out to be a disaster.
Best,
Robert