Joined: Nov 2006
Posts: 19,810
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From: NJ, NYC, LI
Bikes: 1940s Fothergill, 1959 Allegro Special, 1963? Claud Butler Olympic Sprint, Lambert 'Clubman', 1974 Fuji "the Ace", 1976 Holdsworth 650b conversion rando bike, 1983 Trek 720 tourer, 1984 Counterpoint Opus II, 1993 Basso Gap, 2010 Downtube 8h, and...
I'm thinking you meant to put this in the commuting forum, or touring.
A GPS is a good way to do this; it finds the route and tells you when to turn. Though on a long ride battery life can be an issue.
Barring that, carry maps. They get harder and harder to find, but they are the best thing.