I've been watching this, too. Looks like the lake's been loosing about losing about a .1 - .25 inches per day, and that they've pretty much been running the dam at full capacity. Even so I would guess that it's not going to be really wadable by memorial day, which is a bummer. Just my guess, tho - I'm not able to see beyond the numbers online.
It might be really crowded, especially memorial day weekend, but the Lower Mountain Fork might be your best bet if you've got trout on the brain. The Blue River has some really nice river fishing, though I wouldn't bet on getting any trout at this time of year, mostly bass and sunfish from what I've caught/heard. I've done it as a day trip from OKC, but there's also some really great camping right on the river that you might want to check out. There's a yahoo group that has some good maps and info about the various sections, if you're interested.