If you can go out and ride 30-40 miles you can ride 80, so don't worry. The first time I did a tour on my own to get ready my longest ride was 34 miles. The first day of the tour was 65 the second day was 85 and on and on.... And the thing I learned is that when I do a ride on the weekend, its always 'well I have to do this when I'm done, and do that...'. Then I did my tour and there was nothing else, it was today from point A to point B, that was my only job for the entire day, so no problems. Have a good trip.