I've been watching this thread with great interest as two years ago I did the Moonshine SS 1,000 for my first IBA qualifying event. Being in Chicago I did the Chicago to Sioux City to Casey route. Before I left I though of it a lot like Allen_C is thinking. I even left Chicago at 2:30 in the afternoon. It truly would have gone much the way Allen_C is thinking were it not for the fact that when I got to Sioux City, IA (the half way point) the sky opened up to down pour. I took a rest, gas and coffee break for about an hour and the rain just kept coming. Ignoring time honored advice I got on the FJR and just kept going through the down pour. It turned out that I 35 was under construction from Sioux City to Kansas City, MO. Between the rain, cold, construction and down pour those were miserable dangerous miles. By the time I was on I 70 in Missouri on the way to St Louis with it still pouring rain and the sun coming up into my face going east I was exhausted. With spots in my eyes and being cold and miserable, I found a gas station on I 70 with a MacDonald in it. I ordered a coffee and found a table in the back to nap at. An hour and a half nap and I was back on the way in lighter rain and a happy ending at Casey.
I finished in about 21 hours partly because I took another two hour break in Illinois to return business calls and rest my eyes. Somehow the lesson I learned, luckily at no cost, is to expect the unexpected and that ending without mishap (accident) is better then ending on time. The first and most important rule to long distance riding is to finish without an accident. Therefore when your eyes are having trouble or your concentration has gotten down to the "E" for empty a break is an absolute necessity.
I don't think that the route for the Indianapolis-Little Rock-Casey run takes them on the Arkansas back roads. It's slabs the whole way. That takes a lot of the dangers of night ride out of the run.
I agree completely with the advice that others gave about staying in Little Rock. A prolonged rest stop at the half way point will leave almost no reserve time. If then bad weather or bad traffic strike your screwed. It's probably better to try not to work the day that you're leaving and ride without the plan of a long (4-5 hour rest stop). Figure that you'll sleep good in Casey on Friday night.
When I did it two years ago, after the IBA ride I slept like a log in Casey Friday night, got my burger and hung out Saturday morning and then took off for the Kentucky/Indiana hill country for Saturday and Sunday riding. That was the first time that I rode on Indiana 66 down by Tell City, Indiana. I stayed Saturday night in Louisville and came home Sunday night to Chicago. It was a good experience, except I blew a fork seal on a pot hole on Indiana 66.
Have fun with the ride and be safe. When in doubt play it safe, there will always be another SS 1000 to try. Wish I could go!