Long Distance Competition/Ultracycling, Randonneuring and Endurance Cycling - Help!! Any advice for my cycle would be greatly appreciated!

I'm cycling from dublin to Galway over 2 days (around 200km) for charity in a week and would appreciate any last minute advice offered!! Now i know to most people viewing this forum a 200km cycle wouldn't seem like a long distance, but im posting here because you all must have started somewhere!! I've made a good attempt at training over the last 3 weeks (bin going to the gym to cycle and run alot and have been gradually building up my fittness.... I was an exercise-ophobe beforehand!) And since september I've been cycling to college (about a 25 minute cycle)
A good few people taking part in the cycle aren't taking it seriously at all so i dont feel too unprepared. And we'll be taking breaks every 20km or so apparently.
But I'm still starting to get a bit scared... And I cant back out because I've got loads of sponsors already!!
So any advice???

Just remember to eat and drink enough during the ride. It took me a long time to figure out how important that is. You'll be burning something in the vicinity of 500 calories an hour. The first tour I ever did began with a trip from Dublin to Galway, doing about 100-150 km a day. Cycling across Ireland is great!

- Eat
- Drink
- Rest
- Be prepared for a very, very sore bum on day 2.

Take it easy on the ride. Don't get caught up in the moment and ride too fast - especially in the beginning when your legs are fresh. It's easy to make the mistake of trying to keep up with a group that is faster than you.

A good rule of thumb on long rides is if you aren't able to enjoy the scenery, you're going too hard.

Only 2 days to go now!! And i'm so so nervous.... :( But thanks for the advice! I'm renting my bike tomoro (I own a mountain bike which I use to cycle to college. So I'm renting a trekkinhg bike) I hope I am fit enough to actuall enjoy the cycle! I've raised €300 so far so i'm fairly happy.
Thank you all for your advice! Any more would be greatly appreciated. Especially as far as day before preparation goes. How much/little training should i do compared to my normal training regime? We're leaving early friday morning so I suppose thursday should be a resting day but I dont really know!?!
Thanks!

Good luck on it. Personally, I would use a mountain bike I was familiar with over a better bike that I hadn't ridden. Hate to discover I didn't like a bike after I had just started on a 2-day trip.

A little late, but one other thing is that my local riding is fairly flat but if I get out of town, it's hilly- hopefully you've been over the route before by car.

Good luck on it. Personally, I would use a mountain bike I was familiar with over a better bike that I hadn't ridden. Hate to discover I didn't like a bike after I had just started on a 2-day trip.

I would not change bikes for a long ride. You might put slick tires on your mountain bike if you don't have some already, as it will roll a lot easier than knobby tires.

Have you thought about what you are going to wear ? Make sure your hands, feet and head don't get cold.

Taper off your riding and training over the last few days before the trip.