Don, do you know how she used the set? What her picture settings have been? That is, has she run the thing in torch mode, the way nearly all non-home-theater enthusiasts do? If she has, then the set already is ruined.
How many hours does she have on the thing?
Because you have no control over those things, it's best to avoid a used display of any type -- and that goes even more so for RPTVs.
It's not like, say, a vintage amplifier or even a receiver.