Long Distance Competition/Ultracycling, Randonneuring and Endurance Cycling - First big ride

Hey everyone,
This is my first post, so if I'm in the wrong area, please be forgiving.

I'm planning on doing this year's Ride to Conquer Cancer http://www.ridetovictory.org in the Louisville/Lexington, Kentucky area. This will be my first long-distance ride; as it's a little over 140 miles over September 25-26. I'm 25 and in good shape and have begun riding about 20 miles a day for the last week or so. However, I'm pretty sore when I get off, not because of the fatigue, but from sitting on the seat and the angle at which I lean on the bike. Also, I've included a picture of said bicycle on the post. It's pretty old but, due to a lack of funds, it's what I have for the time being, and what I'll probably be riding during the event.

I'd really appreciate any suggestions anyone can offer as to things I should change, replace, have looked at, remove, etc from the bike. I'm working hard to raise the money required ($2500) to participate in the event and I would hate to have something happen to myself or the bike while on the road, after all this work.

Sorry for being so wordy. And thanks everyone!

If you don't have cycling shorts, get some, they will make a huge difference. It will take some time for your butt to get accustomed to riding, some soreness when you start biking is normal. If after a few weeks or so, you still have pain with bike shorts, you may need to look into getting a different saddle. Saddles are a very personal thing, what fits one person may be a torturous saddle to someone else

Sweet man, Good luck and you will have the time of your life. You will reach many goals in a single day like longest ride ever, largest group ride and my best guess is you will be so caught up in the even you will not even realize how far you have gone until you are finished. Good luck and have fun.

Thanks for the replies guys. I have another question: If I had a chance to put aerobars on my bike for cheap, would it be worth it? Not necessarily for the aerodynamics, but for saving my back. Just wondering.

Thanks for the info!

I'm no fit expert for sure. But generally, people have their seats up higher than that. If you have your seat at the right height, it suggests that frame might be on the large side for you, which would make you more stretched out, extra weight on hands, etc.

There is no concensus in saddles. There are some crummy ones, and you may have one. But it will take some experimenting to get a setup that's comfortable. Definitely work on it before the ride. Crawling on the bike the second day when your butt is still sore from the day before would be rough.