I hear you, Jenn. I think that it's impossible to watch your child get completely messy without flinching at least once. Or twice.
That's when I strip her down naked, or mostly naked, except for an apron, and put newspaper down on the kitchen table (the one that was my parents' long before you knew us!) I got these cute little aprons at Michael's, for $1, so we bought a few of them, and it's so nice to not worry about her clothes getting covered.
But believe me, I much prefer the simpler crafts. Like construction paper and sticky foam animals. Just make sure they're fresh enough that you don't need to use glue to get them to stick to the paper, or before you turn around your child might be stamping the glue stick in a circular pattern around said kitchen table, and on your hardwood floors.
Washable markers are easy, as are crayons. You can use the post I linked to where small crayon scraps are used to melt down into new, large, round crayons with a simple muffin tin! I bet A would enjoy that!
Oh, and another easy activity, which is somewhat messy but simple to clean up is water play. She can stand on her potty stool in the bathroom all day long and fill up the sink w. some water and soap, give her some tupperware and random cups to play with and we're good to go. Simply strip her shirt beforehand or after, and get a towel ready to wipe down the floor and tah dah! So much fun! Bubbles are another fun water sport in our house, but my main problem is that there is no way she can play with them without spilling the entire bottle on the floor. And my poor hardwoods just can't take that to often.
As for your Operation PC, I think it's a great idea. Let me know how it has been going for you. In the meantime I can barely figure out portion control when it comes to food, and being home all day doesn't give me too many options, so I'll have to think it through before committing, but I am FULLY behind you and you have my support! Go forth into this good night ... and day ... and whatever!
And now I have to go stop her from taking the pickle jar out of the fridge ... Lord help us all!