Susan is one of the most experience--if not the most experienced--ultra distance cyclists on TE, so listen to what she says! And good luck in Alaska, Susan! Sounds pretty darn cool.
Granted, I've only done RAIN twice, but I think it's easier in many ways than a lot of centuries, so try to keep calm about it. Easy for me to say, right? I darn near threw up the first time I did it; I was so nervous. But if this helps put it in perspective, I did RAIN the year to the day that I really started riding as an adult. Now, I'd put a lot of work in that year, but still, I was pretty green. The thing about RAIN is that the weather can make or break it. The first year I did it, we had a decent tailwind and relatively mild temps. I average 19 mph and finished in the top third. I felt great almost the entire time and the main thing that nearly tripped me up was the hot toe that I get on my right foot. The second year was rainy in the morning and then humid in the afternoon. We had more a crosswind that year, and again, my hot foot toe near killed me. I could barely breath from the pain. I still averaged 18 mph though. The first year, I did the ride with a riding friend who had just finished a xcountry bike trip. She was awesome. The second year, I rode with a woman who was a regular riding budding. I was slightly stronger than her and we separated with about 50 miles left.
So, with that, here's my advice: Get to the start as early as you can and get as close to the front, right as you can. The start of the ride is nerve wracking. Keep to the right and hold your line. A lot of people will be passing you and there's a lot of crazy pacelines. Just stay very aware of what's going on around you. The first part of the ride has some rollers, but nothing crazy. If you need to stop before the first official stop, I think you go through a few towns with fast food restaurants. Everyone is pretty welcoming. When you get to the first stop, get in and out as fast as you can. There are plenty of port-a-potties, so it's pretty easy to keep it brief. Same with the second stop. The morning goes by REALLy quickly, but as Susan said, ride your own pace. You will be very pumped up so it's easy to overdo it.
After the second stop, the route starts to get a little more tedious. And it gets a lot more tedious as you go through Indy. Just try to stay upbeat. It's a good time to be riding with others for a little extra energy. If you have a SAG driver, lunch is a good time to hook up with them. It'll save you from having to fight the crowd and/or eat food not to your liking. Instead, pack your own lunch and have your driver waiting for you at the school. Restock your supplies there, too. Again, get back on the road as quickly as you can. Lingering at lunch can really sap your energy. During lunch DO NOT forget to keep drinking every few minutes. Just a half hour without much liquid can put you into the hole as far as hydration.
The ride out from lunch can also be tedious and hot. It takes a few miles (or more) to get back onto the groove, but keep in mind that you only have 60 miles after lunch and that's totally doable, right? Keep telling yourself that as you settle back into the ride. The route takes you through some country roads and cornfields before dumping you back onto 40 in Greenfield. Many people meet their SAG driver at this spot for an unofficial stop. If you can arrange for it, I would strongly suggest following suit. The next official stop is still a while away, and it's my one quibble (assuming they haven't changed it) with the ride's logistics.
The next and final official stop will feel like heaven to you. I remember running into a friend whose wife had frozen washcloths with her. He offered me one and it was LIKE THE BEST THING EVER! There's also popsicles at the stop. Eat one! From the last stop, you might be riding on fumes, but it's totally doable. There's a long, but shallow ascent into Richmond, but by this point, people are cheering, and you'll hopefully find the gas to finish.
As I mentioned earlier and Susan indicated, sip something every few minutes. An electrolyte replacement is a must on this ride. I typically took one sip of Cytomax for every three of water. I also took some Endurolyte pills for some additional electrolytes. I had food cut into small chunks that I kept in my top tube bag, and I ate something every 15 or so minutes. Obviously it helps to work out your food and drink preferences prior to the ride. My stomach isn't overly fussy, so I'm afraid I don't have much advice there. I try to eat a variety of things, including some salty food. Paydays got me through both rides.
The dynamic of this ride changes if it's really hot and humid. The year before I did it was awful, and a lot of people dropped out. If you're riding with others, keep on the lookout with one another for signs of heat stroke. It is SO important that you stop riding if you start to feel faint, nauseous, confused, etc. Know the signs to look out for. No ride is worth getting sick. To keep your core cool, put ice in your sports bra. If you have a SAG driver, have a ready and ample supply of ice and cold water and cold, pre-made sports drink. It helps to make sure you are very well hydrated in the days leading up to the ride.
Those are the things that most come to mind. In my limited experience, RAIN is a blast. I'll keep my fingers crossed for good weather and a tailwind. I really wish I was in a position to do it again, but my mileage is a mere fraction of what it needs to be. From that standpoint, it sounds like you are in very good shape. I was riding 200-mile weeks in the time leading up to the ride the first year, but I had only one century (the Horsey Hundred) under my belt at the time. Like I said; I was pretty green. I remember the look on my friends' faces when I decided to do it at the last minute. And I remember the email I sent out when I announced my results wherein I declared that I was no longer "a newb." It was one of my happiest days on a bike, so I hope you enjoy it as much, too!
Live with intention. Walk to the edge. Listen hard. Practice wellness. Play with abandon. Laugh. Choose with no regret. Continue to learn. Appreciate your friends. Do what you love. Live as if this is all there is.
--Mary Anne Radmacher