I searched for a way to combine tracks into a single boundary track and this (Merge Track) came up. The page is blank. Is this a future update? I fish a reservoir with a very large and convoluted boundary. I can't trace it all at once without losing a lot of resolution.

Why You don't use a polygon in Google Earth. You can stop the drawing and start again, if You wish?

Tracks e. g. as gpx You can load its in QGIS, save as shape and merge to a single shape. The same options You can find also in other GPS-programs.

Best wishes
fjordfisher

There are such a lot of ways, that it is impossible to describe all. A few ways already have been listed above.

You could draw your outline part by part in Google Earth, export the kml's and merge these kml's with the freeware RouteConverter, for example. With that software you also can check, if there are overlaps, correct and complete it, export the merged files as one track in a lot of formats ...
To use your track as a borderline, it has to be a gpx, kml or kmz or shp file.

You also could export your single tracks with RM as csv's and merge it (copy & paste) the opened csv's with a simple editor like Windows editor or Wordpad ... sometimes not a bad idea. The merged csv you have to reopen, for example with RM and save it as *.gpx.