This is a weird question, because I don't know you, nor ever rode with you, nor know what kind of time you can give to training between now and August 17th. You have a 6 weeks, if you have the time start training by doing 20 miles a day back to back the first week with one day of 45 miles with a day of rest after the 45 mile day; then 2nd week do 25 miles back to back, one day of 50, day off; then 3rd week 30 miles back to back, one day of 60, day off; 4th week 40 miles back to back, one day of 70, day off; 5th week 50 miles back to back one day of 76 day off; 6th week 60 miles for Mon-Tues, then a 75 miler on Wens, then stop riding till you leave on that Saturday the 17th to give you 2 days off before the trip.

The good news is with this trip is that it's only 4 days, not 2 weeks or some such time.

If you can't put that time in to do that then you may want to reconsider the trip; or if doing these back to back drills and the one long day starts to give you a melt down then again it may be time to reconsider. Sleeping after a ride is not a big deal, just sleep! Make sure you're getting properly hydrated, your urine color will tell you if you are, if it's a darker yellow then drink more, you want a real light pale yellow color. And the ride refueling is important, but I think the tour company since it is supported will be making sure everyone eats, but you need to make sure if that's the case.

And if you have to put it off, then start training for it next year. You can actually do a century training program that you can find on the internet that will get you ready in 14 weeks by customizing it for more then the 8 weeks they show and getting the weekday mileage higher to eventually equalling 75 mile back to back riding but maintaining the longer weekend ride at 100.

Personally I think, note I said I think, you should be able to do this ride. It may take a lot out of but again it's only for 4 days. But if you don't start training now then you may not be able to do it. Keep in mind too that if that 4 day tour is a leisurely ride and not a "see how fast we can get the day done" ride you will fair better because you can go at a slower pace.

I don't know if the training program I laid out will work for you or not, but you will find out if you can handle it. If it does work for you then you will be successful on the tour because it's only 4 days, you trained for 6! Also make the training fun, don't stress over it, I think you're stressing over it too much and that's taking the energy out of you as strange as that sounds. You see this in sports all the time, an athlete gets nervous and they fail, don't get nervous about it and make it fun by taking different routes and going places around where you live.

I too am training to try to do the longest ride I've ever done in my life...200 miles in a day! I'm 60 years old by the way. My training program is based on a Century schedule that I modified to take more weeks to train because I'm going 200 miles and not 100, so I'm hoping by the middle of August to do the trip, I am on target as of this week to reach the goal, in fact this coming Saturday I have a 64 mile ride to do, then every Saturday after that it goes to 70, 77, 85, 100, 125, 150, then 200. Living in Indiana with the wet cool summer we've been having may alter the plans a bit, time will tell.