Good, you're going to concentrate on the southern end then. Vienna is about the only place you can be guaranteed to stock up on any supplies needed unless you can make it up to Harrisburg. Karnak can be hit or miss. From the campground to the trail head in Karnak is a fair piece of work with some significant climbs and rollers but beautiful scenery of the Ohio. You quite likely won't see anyone on the trial until you reach Vienna as the southern end is far more desolate and doesn't see much bike traffic. From Vienna up to the Tunnel Hill is where you will see the greatest amount of riders otherwise you'll probably have the trail to yourself.
Btw, it's VI (long I sound)enna and not VE (long E sound)enna or they'll know you're not local, Ha.