Bailey Canyon is a Colorado classic and is a decent intro to creeking. Have a 100% roll (preferably on both sides) and feel comfortable on class IV and you should be ok. The season is long and people run it close to every day when it's on. It should be easy to find guides for the first time, too. You can walk the 3 class Vs easily and also run them piecemeal if you want. Lots of folks do this at Supermax and only run the bottom.
It's important that you really feel comfortable doing read and run class IV, though. The Steeps are not that hard, just IV-IV+, but most parties don't scout them, so you'll probably want to be ready for that or let the group know before you put in. If you need to scout the Steeps, that doesn't mean that you don't belong on Bailey, but if you're walking them, you're probably on the wrong river.
If you're interested in going Fri/Sun see my post on that. We never mind taking new folks down.
steve