You need to know both things -- where you are right now, and where you're going. If you don't know where you are, the destination is just academic.
Sailors like to say they're "bound for" a destination. We're told not to over-commit to a particular place and time. My limited off-shore experience was a trip bound for Beaufort, NC. We didn't arrive there, we were shipwrecked on an island in the Atlantic. That's another story.
They say that the most dangerous piece of equipment on a boat is the Calendar.
If you're obsessed with meeting a particular date, you may overlook small problems which escalate to large problems.
But an obsession with where you are and where you're going is healthy.
Guides, Charts and Pilots
We've got a lot of resources to help decide where we're going.
Guides. We use Dozier's Waterway Guides. http://www.waterwayguide.com. We've also looked at some Skipper Bob publications. http://www.skipperbob.com. Waterway Guides has just released an iPhone App that contains up-to-the second information on marinas and services.
Charts. We use Waterproof Charts. In our case, they cover the Northern Chesapeake -- down to the Maryland line -- which isn't our cruising grounds.
Charts. Everyone uses the NOAA charts. They have a nice on-line chart viewer that shows the current, official chart.
Pilots. The United States Coast Pilot books, particularly, book 3, chapter 11, covers our cruising ground. The North Atlantic Ocean Pilot (publication 106) covers average wind and weather in the sailing areas.
There's more, of course.
The "epitome of navigation" is Bowditch's American Practical Navigator. It's a 35Mb PDF download. The truly hard-core by a paper edition to use in the eventuality that their ebook reader croaks off.
Everyone needs the International Code of Signals (publication 102). It explains the colored flags. Nancy Charlie, for instance, is the "I am in distress and require immediate assistance".
This doesn't even touch on the international Sailing Directions (Enroute), Sailing Directions Planning Guides, USCG Light List, World Ports Index.
This doesn't even touch on the marine weather forecast information for Deltaville, VA.