Jseis 

When I rode cross continent in '76 we started at ~35 miles a day out of Vancouver BC. We weren't in a hurry through the coast range and Rockies. East of Calgary to Winnipeg we were in the 65 mile a day range. A few weeks later later we had many 98, 100, +100 days. 118-120 was about as high as we got. We were bike packing and carried about 35-40 pounds per person. 100 miles a day touring takes ~12 hour a day steady riding, particularly if you are loaded. I'd think a rider in good touring shape could do 100 miles a day out of the gate but it might take light packing and lots of pre-trip seat time. Out daily pattern was rise, eat, ride eat, nap, eat, ride, ride, eat, sleep. 100 miles a day means burning ~7000-8000 calories a day (say 5-6K + 2000 BMR) and that's a lot eating! At the age of 21 it was somewhat easy...now at 58 I'd need more rest to repair my bod. Early RAM speed averages were around 12mph+ so for an experienced cyclist! it might be possible to ride 8-9 hours in the saddle..burn through that 100 miles and spend quality time resting.....and eating!!!