Someone asked me if I had any advice for them, before their first rally. This is what came to mind, reflecting back on the Capitol 1000.
Get enough sleep before the rally. In the Cap1000 my roommate stayed up really late planning his route, got too tired and DNF'd. I planned my (simple) route and went to sleep. Also, I budgeted three hours for sleep (didn't use it all, but it was there). WAAYY too often you read about someone starting out on a rally with very little sleep the night before. Why the hell would anyone choose to do that? They don't, but they let it happen anyway. Don't do that!
Do as much prep as you can well before the rally. This means get the bike set up exactly as you want it and ride it that way. Don't head out for the rally saying "Well, I only need to connect this to that and re-wire the speaker and replace the coil cord and then I'll be ready." Make sure everything works: make sure your water is accessible, the tank bag (if used) can be easily moved to add fuel without disturbing other stuff, etc. My commuting setup is pretty much rally-style, so I was in good shape. Make sure you're comfortable on the bike for long distances, practice your gas stop routine, and keep your paperwork (route sheets, directions, rally pack, pen) in an accessible but dry place.
Get a map of the whole rally (if possible) and mark all of the bonuses on it, with point values. In many rallies, bonuses which are listed on one leg are best taken on another leg. In the Cap1000, some bonuses listed on the last leg should have been taken on the first. Set drop-dead times at which you MUST be at certain locations, working backwards from the finish. And know your speed: I planned on a much slower speed than I actually made, which hurt me. I actually averaged, OTR, about 55mph including gas stops and bonuses. Set a route and write directions for each section with approximate times. You may want to make a flexible plan, like "If I get there before this time, I'll go for that bonus. Otherwise I'll only go for the other one."
Follow your plan exactly for the first section (unless it's obviously bad) to get an idea of what your actual performance is like. Then if your plan proves to be too aggressive or too conservative, you can re-think it. Of course, the re-thinking is best done in advance (plan B) but that costs sleep.
I found the Cap1000 to be easier than doing 2 500-mile point-to-point rides. Taking different roads, riding for a different reason, looking for different things, and stopping at different places made the miles roll up far more easily than on any previous ride. If you think you'll need sleep then you probably will, so plan for it. Remember the deep knee bends: they are magic!
My write-up shows how I started off with a very conservative goal in mind and got more aggressive when I saw that I was doing better than expected. However, it was too late to really think out a non-baseroute plan by that time, so I just made an aggressive baseroute out of it. I can't really say how you can stay out of that trap, since I (and probably you) don't know your real performance limits. Also I don't know what your goals are. If you, as I did, just want to finish the rally, then follow the same plan as I had. You will still beat some of the big dogs! If you're out to win, good luck! The only way to do that is to plan your ride to the last detail and know yourself REALLY well.