I'm a nearly-WAW who is trying not to be one (hoping to get this thing back on track before I bail, because I don't think I'd go back).
I'm projecting a bit, but if you can maintain the breezy, upbeat tone and at the same time say something like, "oh, the kids and I are going to the movies as a reward for ..." and include some chore you have done together that used to be only her responsibility. Like cleaning the first floor or cleaning up and organizing their rooms, maybe. I'm trying to think of a breezy way you can convey that you understand that the work she did was something of note, something extra and not as fun as watching TV or shopping or whatever.
I would be VERY careful not to overdo it, though. Once a month is often enough, or it will start to sound forced.
In terms of doting on her without pressuring, have you tried a light compliment or noticing something about her appearance? Even something as casual as, "Hey Susan, that's a good color on you, thanks for dropping off the kids" would work. Breezy, light, and casual are important I think in every interaction.
