I've used Google Earth for years. I also use this free GIS software:
Quantum GIS . You'll need some computer skill for the GIS, but it's not quite as intimidating as it might seem. Plan on spending some time to learn how to use it effectively. Once you are proficient, you can build maps onto topographic base maps by adding free data layers from wildlife agencies, other natural resource managers, etc., that are extremely helpful for hunters.
Sometimes, however, you just can't find a data layer that can be added to Google Earth and or the GIS. Maybe you need to add an image that's only available in printed form, for example, a trail map. This is actually pretty easy on Google Earth, but it requires some time to get it done right. Use the Google Earth
User guide > Importing your data > Importing Image Overlays for step by step instructions.
Here's a plain English version of the instructions:
Scan the thing you want to add. If you don't have a scanner, you can get this done at Kinko's, Staples, etc., or you can take a digital photograph (use a tripod if possible.) Add the image to your computer system with whatever software you have to do that. It has to be one of these formats:
BMP
DDS
GIF
JPG
PGM
PNG
PPM
TGA
TIFF
If you start storing such images systematically with a specific file location, it will help a lot down the road.
Now, open Google Earth. Center your view on the place you want to add the image. Try to adjust the scale so that what you see on the screen approximates what you know (or guess) is the scale of the image, but don't get too anxious about that.
In the Google Earth top menu, click "Add>Image Overlay." Click "Browse" to locate the image you want on your computer system and add it.
Now, at this point you will have something laying on top of the Google Earth image. Over in the Google Earth Sidebar, right-click (Control-Click for some Mac users) on the name of that "something" under Places. A popup appears showing some choices. Click on "Get Info". You'll see a green grid superimposed on your added image. Don't fiddle with it yet.
First, adjust the image transparency (using "Get Info" again) to make it about 50% opaque. Now you can see the underlying Google Earth image.
Now you can drag your image with that green grid and adjust its corners with the grid as well. Move the image until it lines up approximately where it should be. Use the corners to match it more closely with identifiable features on the Google Earth image.
Once the image is added as you want it, save it to your Google Earth Places.
Now comes the amazing part:
Because the image is "draped" over the Google Earth image, it adopts the 3D contours from Google Earth. In other words, you can see how a trail or boundary or whatever you've added follows the terrain in a 3D view. And you can print the whole shebang from Google Earth and carry it into the field.