I'm not in nearly as good shape as you and I average 50 miles a day on tour. Of course, I have to pedal my way into shape so the first two or three days are shorter. Touring is different from training for me, partly because of the load, and partly because when I'm training I never seem to do long rides on several successived days. I might ride 2 out of 3 days if I'm lucky. When I tour I generally only take one rest day per week, and often go two weeks before a rest.

Anyway, lots of long distance tourers average lots more than 50 miles a day. You'll do fine. Have a great time!