Aside from events, and the occasional short tour, I don't deliberately follow standard routes.

On many of my tours, I pick a destination I want to see ... and cycle off in that general direction. Sometimes, I make a decision about a destination before the tour, sometimes it is in the middle of the tour. I usually start a tour with some sort of general road map, but I'll pick up other more specific maps along the way as I decide where I'm going to go.

I don't think I could do one of these "Northern Tier" or "Southern Tier" cross-US type of tours ... I'd feel too tied into a route and would want to head off in different directions every few days.