I use Reefmaster(Custom Paths) and Google Earth(KMZ) for track maintenance.
First I have to setup. I will export any new track data from my sonar unit(GPX). I will import from this new GPX file into RM. Then use RM Write to File as a Google Earth KMZ for the track.
Then I will Edit(or Create a new) User Map, click Edit Tab on upper right of RM screen and set Group as Custom Path which now give option to import that KMZ track which will add that new track-segment to the User Map. The edit panel will display each track-segment of your track with the number of track-points in each track-segment.
So now I have my tracks as User Maps using the Custom Path method.
So now you can Edit a User Map, zoom-in on the track area desired. Left-click on track, then Left-click Edit Tab and Edit Window will open with the selected track-segment highlighted. You can edit the track-segment's color, line-width, etc. You can also delete track-segments in the Edit Window. You can Right-click a track and are given options for that track-segment part of the track. I wish the Edit Window would stay open as long as I Left-click track-segments, but it does not, so you have to continually re-open it.
Reefmaster and Google Earth both handle tracks with track-segment very well. I create a Lake folder under GE's My Places and save all my track KMZ's in those folders. This results in my tracks being backed up in both RM and GE.
Most time, I use Google Earth to edit a track or a track-segment since GE gives a satellite image as a background.