Some parks will agree to transport your personal boat or raft of you pay a fee for their liability insurance. I don't believe there's a two hour option with meramec though. There are a couple campgrounds and public beaches along the way though if you wanted to DIY your float trip transportation.
It's a 5 hour journey. With a pre selected drop off site. Can't say if such a point existed where you can make it in 2 hours. And about your personal raft I'm not sure about that. they have ones on the ready for you already
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