Michael,
Google Earth is still one of the best trail creation tools available. I always use it to make changes to straighten trails and reduce the number of track-points for tracks and create tracks with track-segments.
You did not mention what units or Reefmaster programs you use, so I will stay only in Google Earth. Though, I suspect you are using Lowrance units and Reefmaster Waypoint Manager for Lowrance(GREAT PROGRAM).
Google Earth can open KML/KMZ/GDB/GPX files, so best you need to export from your units in GPX format if possible. On opening the GPX, GE will prompt you for the following and you should check/uncheck the following:
Create KML Tracks Uncheck
Create KML LineStrings Check
Adjust altitudes to ground height Check
The GPX will be opened in GE's Temporary Places. You should completely expand the data. GE will create Points & Path for you GPX track. You can uncheck Points.
For the most efficient tracks, you will want to create a new Folder in GE and create a new path by tracing the sections you want.
Create a new GE PATH in this Folder for each individual section. Think of the GPX sections as a tree-structure with each trunk and limb as a new GE Path in the Folder.
Save the Folder as a KML/KMZ file as necessary, and you will need a program to convert to the necessary file-format your units require(GPX, USR, etc).
Note here: Reefmaster program will support track-segmentation. Reefmaster Waypoint Manager for Lowrance will not support track-segmentation using KML/KMX, but does support it using GPX/USR.
AN OBSERVATION:
Lowrance units create fairly efficient trails. Humminbird units create VERY inefficient tracks. Efficient or inefficient in the number of necessary track-points created. The most efficient tracks only have track-points if needed or ideally only when the track has a change-in-direction. I.E. A straight section of track only needs 2 track-points, start and end.
Humminbird units create track-points by default every 7ft. So for a straight-run, 3 track-points are created with a 21ft boat for the stern to reach the bow. Also Humminbird tracks will disappear if you zoom-in too much and the track-points are too-far apart. In creating HB tracks, have a track-points no more than 200-300ft distance.
