If your mast height is less than 50 feet above the water; you can have the mast up, once you get to St. Louis. It's a lot more pleasant without the mast in the way. You can also sail in some of the lakes on the way.
I've gone from Kentucky Lake Dam to Mobile twice in the last few years. You shouldn't have any trouble with your boat if you stay in the channel. There are a couple marinas along the way that you won't be able to get to with your 4 1/2' draft, unless they have dredged the channels. Call ahead and check.
I had to anchor just outside the channel a couple times, because I motored an average of 12 hours a day, and couldn't make it to the next lake. You can usually plan ahead, though, and find good anchorages. You'll need a good stern anchor as well as bow anchor. I always anchored bow and stern in line with the current, so I didn't swing into the shallows. Be sure your depth gauge works well and is accurate.
I have a few videos posted from my last trip.