Mary, honestly - that is quite a stretch. I did an 8 day/65 mile/day tour once and before I went, I was riding several consecutive days ~ 50 miles/day.

The thing that really hurt after about 6 days was the "nether regions." I honestly did not know how I was going to ride the last couple of days - it was shear determination to finish. And I had good shorts, saddle, custom bike, etc. But (pun intended!) 4 hours in the saddle for 6 days = 24 hours.

I agree that training *for* something helps motivate. Is there something else you can set your sights on that would be a one day ride?