First - get out of advertising.
As far as maximizing the 15 miler ride - I'd start with intervals. Do you have a heart monitor? A HRM would help you to raise and manage your overall effort level - especially if your doing intervals and increasing your effort on any hills.
Now, get back to work. There's a new client meeting in 2 hours and the creative brief - that for some reason was written by the traffic person - is completely off strategy. Meanwhile, the head of Account Services is sleeping with the new jr. art director and his wife wants to know what you are going to do about it.
55/Rad