Thanks for the replies. First off, I do change it up. Last night I did a Chris Carmicheal interval workout for 60 minutes then finished the last bit to get 15.
today's 10 was a "recovery" ride, less resistance slower speed.

At the hardest part of the interval my HR was about 165 by the bike. It seems to stay between 140-150 the rest of the time.

The 50 miles will be some flat some rolling hills. the 60 is all flat. the century is mostly flat. BAK is mostly flat some rolling hills. The others I don't know, never tried them before.

Last year I did the Wicked Wind 100. That's May's century.


Kim