Polish the SS it will be a better surface than any other type of coating. There may even be a shop that will spiff it up for you that has the proper polish tools and compounds...you can do it...read up on it and buy the polishing bars and use a buffer...That would keep it in character and go well with the full hieght SS back slpash or diamond plate. I'd do the full board repalcement by the bed area and sink as suggested...just will be more usable and keep stuff on the bed from falling in the sink! Plus keeps the bedding cleaner as well from cooking and washing.