Hawksey, I haven't had any personal experience, but I would assume that like Janine said, if you are not there, your DD will likely just as easily fall asleep a different way. No doubt she'd be upset if you tried to put her to sleep another way (i.e. I know the boobs are there, why can't I have one? But she's old enough to know that if the boobs aren't there, then that option just isn't available, KWIM?). Course, that's a guess Only one way to find out for sure!
I would think that if you are only feeding 3 times per day you won't notice a massive drop off in your supply. Lots of people feed sporadically in the toddler years and your milk sticks around for ages.
Again, this is without any personal experience, only what I've heard from others. Unfortunately, we weaned at around 11 months. And even though DD was completely weaned, my milk stuck around for a couple of months after (in one breast... Don't get me started, LOL! I'm a weird one).