Good morning! For a table runner that will remain on the table during meal time I think one about 13-15" x 26-30" works great--this size wouldn't interfere with the place settings and will accommodate the more narrow tables. As for the buffet 15" wide is about right and no more than 48". JMHO.
I like the creams and golds idea. I'm working on a simple checkerboard with 50 2 1/2" cut squares and a blue paisley gold metallic border. This is a 50th anniversary gift. One of the CB fabrics is a metallic gold paisley on cream background. This is really simple but very pretty. Need to get it finished.
Have to be in town in 45 minutes so better go. Catch you all later. Keep your snow an 1 1/2 away QE!