You literally do not require maps, compass or gps for this trip. Bring them if you like but wasn't required. The trent map fold out you can get from any lock was more than enough.
Trent waterway for the most part is clearly marked and there are only a few spots where you have to stop and think about it.
I did have gps on my blackberry and it was helpful, used it to gauge where I was not really for navigation. If travelling at night, recommend gps of some sort, on water in familiar area at night is fine but in areas you have never been, everything is different, not a time to get lost or disorriented. I also had a handheld gps which showed speed and distance traveled, either don't bring or stowe and don't look. Found myself constantly checking it, how fast am I going, how far have I gone, turned mine off after day and a half.
Here are some tips.
Simcoe, when you come out of the Orillia Narrows and follow to the left, you will jump a few points and then will just see horizon line in the distance, looking straight across you will see what looks like a point in the distance (barely) wasn't sure if I had to go around it, it's an island and the channel is to the left of the island. Just head for it and when you get close enough to make out the island head to the point on the shore to the left and keep following shore to channel. Needless to say, if weather is up and Simcoe can pick up quickly I might suggest hugging the short instead of being 5km from shore in bad weather.
Canal lake, the lake splits around a big island on the opposite side, stay on right side, you will see a bridge with like a half moon tunnel, just go under it.
Balsam lake, when you come out of canal, just head to 12 o'clock and you will hit the island, depending on wind either go right and around point, way the markers go, or go left and around the long way. Rosedale is on opposite end of island at the far left. Update: Best to go left and around the island and not right, where the waterway goes, shorter and easier in the wind, learned that in the 2010 Trip.
Cameron lake, almost no markers so at first hard to tell if you should go down left or right side. Fenelon Falls is down the end on the left, look for white buildings on shore and head for them, when you get to Fenelon Falls make sure you enter lock between the two markers (red triangle and black square) there are rock walls that line channel on both sides, can't cross over if you miss and will have to circle back.
Bobcaygeon, when you leave and come out of channel, it looks like you go straight towards the left, don't. Go right and follow the big island on the left. Don't get discouraged, looks like a long way, channel is not that far down pigeon lake on the left.
Peterborough, when you come out of Ashburnham lock you will see markers leading into Peterborough on the right and will automatically head that way, at least I did. The next lock is straight towards the bridge on the left not in Peterborough.
Bay of Quinte, when you come out of Trenton you will see markers heading towards the island on the left, run parallel to the island and you will see the markers in the distance to the entrance to Murray Canal. Red triangle. At first you think you have to go down right shore because there aren't many markers past the island.
The above are the only spots where I had to think about where to go