Hi Lyle, This is not hard. Typically, you would have installed the baseboard in the dining room first and covered the edges with shoe molding after the flooring is installed. But to do it your way, the baseboard now should be run through a table saw to reduce it's height by the thickness of the flooring. This will allow the two levels to match perfectly. I would still install the shoe molding to give a traditional finished edge to a hardwood floor and cover the somewhat ragged edge of the ripped basebaord. It should all look great when finished.