I will answer today so that I do not cause you any more frustration with getting photos.
A service for 12 in the Apollo shape, Radisson pattern china made by WS George Co of Pennsylvania; the pattern first introduced
in 1941 and discontinued in 1959, has a current value of $400 to $500 retail.
You mentioned Derwood, that is a different pattern than Radisson. I will add photos of each, Derwood being the pattern with the bouquet in the middle. The value for a service for 12 would be the same.
As for your grandmother's set of 'Rosendale' China. I think maybe you mean Rosedale? There was a pattern with this name made by 11 different makers, so let me know more succinctly what the bottom of one piece reads. Also let me know how many pieces are in this set.
Some sites that I recommend for selling are Varagesale.com, Ioffer.com, OfferUp.com, Ebay and letgo.com.
You can also go to invaluable.com or liveauctioneers.com and search their directory for an auction house near you and consign to them.
To finish, I will need you to click the five stars at the top of your screen and hit the submit button, thanks! No worries, we can still talk here about the other set after you click the stars.